What's the most manipulative thing you've ever done?

I have and will continue to make a small number of obvious omissions or minor misspellings in my work when I submit it to my bosses for review. Not in the majority of my work, but mostly when they may have some resistance or hesitation on a course of action or a part of the project.
If I can trick them into contributing to the project by fixing or improving it, they end up feeling ownership of it in a way they wouldn’t have otherwise. I do this on purpose, and turn a hesitater into a champion of the work. It’s our project now!
- I ask leading questions that make people think an idea is theirs. Business people love their own ideas. A woman's? Not so much.
  
  😢
- That’s kinda genius ngl
  
  This is an example of "managing up". It requires understanding people well, a particular weakness of mine.
- Oddly enough I have done this in reverse to Jr members of my team. Amazing the engagement you get when they catch something they see as obvious, and thanking them brings up moral.
  
  In this case it's "morale."
  Waaaaaaaait a minute...
  
  It’s a win-win for everyone. Plus, if the person misses the obvious thing, you know what not to trust them with in the future!

Not the most manipulative but
Keep a log of the birthdays, hobbies and names of spouses and children of colleagues, managers, team members and customers.
I learnt this from a guy who did executive search. People remember you, when you remember what is important to them.
When I've lead teams it's one of the first things I find out - note down when someone says "yeah Gary that's my hubby, he's super into gaming"
Gary (husband.)
likes gaming
When you're a manager, your teams families, partners and friends know your name. Reciprocating that - learning who is important to them - is really important.
- To me this seems less like manipulation and more like you put in the effort to not only be a good boss, but a real person.
  
  If you care you’re a good person. If you pretend to care in order to network then you’re being mildly manipulative.
- Has this ever backfired on you? While your motive is wholesome, I could see the practice itself seeming creepy. Like keeping notes of someone else's life.
  
  Yep. There's people that want to keep distance at work and don't appreciate it. Just have to respect that and leave them to it.
  
  I find it less creepy and more disingenuous. But I can appreciate the intention.
- I do this too; it's a great way to get to know your team and develop genuine bonds. People generally enjoy when you show signs of caring and interest in them beyond their work role.

When I was at a small company that worked with radioactive material, we had to register and secure all radiation sources, even the extremely weak ones that anyone can order online with no restrictions. Before the state inspector came, we deliberately left one of those weak sources out where it wasn't supposed to be so that the inspector would find something wrong, tell us to fix it, and leave feeling like she did her job. It would be the smallest possible violation and it wouldn't actually get us in trouble. We did that because we figured that if there was nothing obviously wrong, the inspector would look for problems a lot more carefully.
(Nuclear physicists are rather more nonchalant about radiation than the average person is, for obvious reasons. By nuclear physicist standards, we didn't actually have any dangerous sources at all. Thus we felt like we weren't doing anything morally wrong, but I suppose that the average person might have disagreed.)
- meanwhile the last NRC audit at my workplace, the inspectors didn't even use the hand and foot exit monitors on their way out. 🤦‍♀️
  I actually worried for a bit that it was a test and they were looking for someone to stop them, but nothing was on the report. smh
  
  Ages ago, I was part of a department that was subject to a compliance inspection. The inspection wasn't a surprise, but it was short notice. We spent days making sure that our two networks of hundreds of computers each were compliant (they mostly were) and that our documentation was up to date (it mostly was). They spent their entire inspection looking at two internal DNS servers. (They passed and we were praised for our higher than average compliance.)
- We had great health inspectors at my former food service management job. There was no way to conceal that we had mice. But the mice never touched the food. My district manager had made a room towards the back into a chill meeting room with couches from Habitat for Humanity. Those couches turned into their nests.
  I went so far above and beyond to fix the mouse issue. I tore out a drop ceiling in one of our dry storage areas with no training and no protection. I was getting below minimum wage at the time because I was on the lowest possible exempt salary. I got showered in mouse shit and who knows what I breathed. I did this because the inspectors were cool and wanted to help us with the problem instead of shut us down.
  They forced us to use glue traps through which I disagree with morally versus kill traps. I used oil to set many mice free. Most of them probably went back into the store.

I work in web dev and one of my jobs is to get you to engage more.
Maybe it's buy more products.
Maybe it's read more content.
Maybe it's click on the button.
Maybe it's like and subscribe.
Sometimes I do it with good UI. Sometimes I do it with dark patterns. Sometimes I do it by not allowing you to opt out.
I also get data to increase that number based on human behavior.
The worst part -- im one of millions of people and companies who are doing this. We are all wanting your attention.
- Wish I would land a job like this, to poison the data.
  
  yeah, sure
- Yeah, but most websites look like garbage, and the first thing I do if I see popups, unblocked ads, or bad design, is close the tab.
  Is that intentional?

Maybe not the most manipulative, but it’s the first thing to come to mind..
When I was 21 years old, I was dating a delightful lush who was 19 and it was a bummer that we couldn’t go out drinking together. So, I found a marriage certificate online, put our names on it and printed it out, then copied it. We also went to a department store and spent $20 on a convincing cubic zirconia ring. We pretended to be married because my state’s antiquated laws consider wives to be property of husbands in this regard, so voilà! We could now go out drinking together! And boy did we, haha.
- Property?...
  
  Yeah, like livestock! Or a small child! What a time to be alive!

Every time I need to buy something at work, they ask me to research three options.
I already did the research. I can tell which option is the best one already. So the two alternatives are always more expensive, and I tell them that "the cheap one" will work well enough.
- My employer has a “buy American” policy that kicks in for purchases over a certain dollar amount. To get an exemption, you need to identify 2 domestic options and state why they aren’t sufficient.
  Recently I needed to replace a module in an existing system that happens to be made by a non-US company. There is literally no valid alternative - only this one company makes the modules that are compatible with each other.
  So I had to identify 2 American made products that were vaguely similar and state why they didn’t meet our specifications. Though “Vaguely similar” is a stretch - it was equivalent to explaining to someone why you can’t buy AA batteries to replace a car battery.

I sell things for a living. I only tell the truth, and I make sure to give all information that is relevant to health and safety, and I try to avoid any situation where someone could say after the fact that they didn't realize there would be an additional charge. After that, it's all fair game.
Body mirroring, nodding slightly when asking questions you want them to agree to, code-switching, listing my preferred choice last in a list of three things, these are the basic techniques.
Next level up is the perception-altering stuff: "we" have a problem but "I" have a solution; if I know they're happy, saying "I'm so glad you liked my recommendation"; instead of "how is it?" asking "how are you enjoying it?"; taking personal credit for all good feelings they have during our interaction (gotta be subtle about this, but it's very effective); acting like they're doing me a favor (people like those they've done favors for more than those who do favors for them... it's monkey-brain social status thing).
For me, this is just Tuesday.
The double-extra stuff comes out for job interviews. I will alter my speech patterns and hairstyle to give the impression that I'm a decade younger. I will tailor my anecdotes to sound like I'm either single or newly attached, with no kids, and vaguely imply that I'm homosexual if the vibe isn't too conservative.
- Are you neurotypical? Because this sounds like the advanced version of what autistic people have to do to fit in.
  I'm not autistic but I am ADHD. I do a lot of code switching. I worked with a new Dominican guy last week. My Spanish is bad, his English is perfect, but I mapped out in my head how to say something good about Dominicans in Spanish, and had a couple responses ready depending on how that went.
  He thinks I'm a great teacher. I am, but that Spanish thrown at him suddenly while we sat together... who knows? He's not important to me for money or social reasons, I just want him to be cool with the job, to succeed, and reach out to me if he has problems.
  I run simulations of how interactions could go and have conversational threads planned to at least A to B when I have time to prepare. It's not like I'm bad at socializing, I just prefer being alone or with my wife. Right now I'm totally by myself, my wife is away, I'm drinking beer with our cats. It's perfect for me.
  
  I strongly suspect that I have ADHD, but a lifetime of masking makes it difficult to be professionally evaluated.
- Aka social engineering

Took me a while but I learned one of my managers is highly likely to shoot down any idea that isn't his. So during planning sessions I started describing partial ideas and pretending I didn't know how to solve the last leg of the problem so he could jump in and say, "Oh, what if we did..." Still kind of pisses me off I have to feign ignorance but since I started doing that things have gone way smoother.
- This is a good way to get your ideas implemented, but your manager is always going to be able to take credit. If you are able to develop a situation with your manager where they see you as equal or near equal, they won't mind if you bring them in on emails or meetings or whatever with their boss, so you can take the credit you are due. Extra credit if you get them to set up the call or meeting with the three of you and then you get to lay it out.
  
  Yeah the problem with that is that the basic reason that they are like that is they are threatened. They have a need they are addressing with shooting down ideas.
  Brian would do better if he addressed that need. I would bet if he started attributing his own expertise to this manager, and started saying things like "wow I've learned so much from you" his ideas would be accepted and credited to him. Brian's success was due to his manager, after all.

I talked two people out of suicide. I guess you could call that manipulative, but in a good way.
- Depends. Did you talk them into suicidal ideation beforehand?
  
  Nope, one had suicidal ideation because of being harassed by people, the other because of an abusive relationship.
- Can you manipulate me out of depression?
  Nah therapists have tried, they failed... 😕

When I was 20, I started hanging out with a girl who lived in my dorm. We made out and went down to bottom underwear, but never really went far, because she wanted to be sure I wasn't just after sex. This was because a month break was coming up.
During the break I chatted with her on AIM every day, while I was fucking a girl I went to high school with regularly. I never told her. After the break we started fucking and then I dumped her after a couple months to find a new girl. I was a ravenous asshole.
My karma is here now, because my mental health issues are finally treated, my libido is near zero due to aging and medication.

Back when I was preparing to propose to my now-fiancee, she figured out very fast exactly where and how I planned on proposing. I didn't want to change my plans, so I lied my ass off for the next month to convince her that
There was no way that I could propose on that date because the ring was still in Canada/Michigan/Guam/Pennsylvania/Kansas/Indiana/etc.
Even if I did, I can't do it where I wanted to because she's expecting it now and I am adamant that she be surprised
Kept all my plans the same, had the ring the whole time, everything went according to plan. She was completely suprised!
That said, the stress of keeping a secret for so long apparently wore my immune system down. An hour after putting my ring on her finger, I was suddenly nauseous, exhausted, a bit dizzy, and running a high fever. So now she has extra proof that I will never lie to her.
- My wife knew I was going to propose because we went ring shopping together. However, she didn't know when the ring was to be delivered and so didn't know my plans. The night I did propose, I took her to a fancyish restaurant; she told me later that she was trying to figure out where I was carrying the ring.
  I wasn't, though. Before taking her to the restaurant, I had consulted a mutual, female friend who said that my wife would be expecting it and I should propose when we got home.
  I did so, but before I did, she went upstairs. In my nervousness and excitement, I was waiting at the bottom of the stairs, ring in hand, and failed to notice that she was carrying a stack of laundry as she descended.
  And that's how I proposed to my wife while she was holding a pile of dirty underwear.
  edit: I hate it when my client decides to post half a comment without consulting me.

Not the most that I did, but I needed to help out a friend in college.
A friend wanted to get out of a group for a class because he was doing a lot of the work. I helped him come up with a strategy.
He was able to pull together a group of friends in non-responsive or disintegrated groups into his. He could then sell to the professor that he was being proactive in getting this group made as it would be easier for the professor than handling the fallout of these people not having groups. He could then leave his group while focusing on pulling together this group; that other group totally did enough work that they could go off by themselves.
He was able to get the professor to approve the change a day before a major due date.
Apparently, one of his group mates was able to figure out that I had to be involved because of how slick this went off.

I manipulated a whole family to care for me for a bit under 20 years. I believe people call such act "being born"
Jokes aside, that I can think of, getting my ex to ok an open relationship. Ironically, I didn't go out with any other girls in the meantime.

- Heh
  
  I want to acknowledge that this was amusing, but I'm not sure how to do so with clear sincerity.

In person I am fanatically polite and helpful to almost everyone. But if you piss me off I will make you feel very bad about yourself.
- Mom?
- I'm the same way, except instead of making you feel bad about yourself, I will feel bad about myself for feeling so angry at you.
  Then if I'm upset enough, I will become moderately less polite or, in even more extreme cases, drop any joviality from my voice and speak to you only in monotone.