What's something you did because you believed society expected you to do it and later realized that you actually didn't want that?

Fitting in. For a long time I tried to be the sort of person people liked. Unfortunately, I couldn't really pass as normal, and ended up more akin to a cross between Sheldon, and the main character in the Lego movie.
I finally realised I didn't actually care about fitting in. Instead I focused on becoming the best version of me I could. Centering myself and accepting my weirdness helped a huge amount.
Ammusingly, I now "fit in" far better than I ever did. I've gathered a collection of friends who match my vibe. People either think I'm weird, and back off (I don't really care about those), or think I'm weird, and that that's awesome. It turns out, my fellow weirdos are far more fun.
- Human beings don't seek to fit in with others because of a societal expectation necessarily. Biologically speaking, it is beneficial for us to be amongst a group. We rely on others to survive.

Goto college. Tried it out for a year. Went back to the work force. Good career now almost 20 years on
- Same. College is a racket. Only a handful of fields truly need a degree. The rest is a cash grab. 15 years into my career and am always the only guy without a degree, yet one of the most knowledgeable.
- If you don't mind, what do you do?

It's super silly, but eating a snack cake. I was a teenager, sitting on my couch at home and I was eating a snack cake, like Little Debbie's, or Drake's or something when I realized "this cake is awful." It just didn't taste good. Like, not that it went bad or stale, it just was crap. And then I realized I was just eating it to eat. It was purely empty calories. Made me a lot more cognizant of what I chose to eat.

Drinking alcohol. I never enjoyed it, but I used to have a beer when I was out just to fit in. Then I stopped because I realised it made me feel like crap, tasted bad and had no redeeming qualities. Now that I'm older I'm comfortable saying I don't drink.

Have relationships.
It's far better being single.
- Having experienced both, I think it’s more accurate to say having bad relationships.

“Be successful”.
It’s not entirely bad. But there’s a lot of baggage in the idea and it masks a lot of what’s actually going on which is finding a place in the world and understanding yourself better all while playing a game for the success that you may not care for in the end at all. The whole thing is more branding than many let on and it’s very attractive to the young mind.
EDIT: makes -> masks

Running up for having a first sexual experience at 22 years old and it was so traumatic, disgusting and makes me hate intimacy forever.
- How bad could it be ? Are you male or female ?
  Is it voluntary in both side ?
  
  I am a male, and yes was voluntary from both sides. It was bad because rushed, so no feelings, bad erection and generally fell wrong, ended with even no orgasm, just sadness. She was a girl and I think she ended with my same conclusion, on rush for having sex without any good feels dedication with a barely wrong idea of what to doing, we treat us like no human at all, horrible and traumatic.

I nearly got my ears pierced when I was 10, but right as I was about to go to my appointment I chickened out and I will be forever grateful. I didn't really care for jewellery then I still don't now. Piercings especially seem more annoying than anything to me.
It took until I was 16 for relatives to stop gifting me random pairs of earrings, though lol

Piggyback my relatives with my income because collectivism ideology of culture. I don't want, and I still not find a logical purpose for this.
In fact, I just asked on Lemmy day ago.
https://lemmy.world/post/1529311