So. Without trauma dumping, I'll simply say my dad is a bad dad. What's a father's day gift that says "you're dead to me, but I'm still doing things to keep drama at bay"?
Nothing says "I have fulfilled my social obligation, but I don't give a shit about you" more than a low value giftcard for somewhere generic.
Alternatively, give him a halfway decent gift and feel better about yourself for not continuing the cycle of neglect, even when he won't appreciate it. We can make the world better, even for those of us that don't deserve it, and considering how to make it a better place as opposed to how to get back at the people who make it a worse one is just a better use of our time and energy.
Besides, at the end of the day, truly awful people already live with the worst punishment so could imagine: having to wake up every morning and continue being themselves.
Make it 20. 10 is too obvious a slight to any onlooker. 20 still won't cover most mains post-covid after tax and tip (depends on your region and the restaurant of course).
Yeah, I think something like 15 would be the perfect "fuck you" amount for something beyond Starbucks and fast food. Enough to make it worth going, but only really enough for an appetizer.
Or be really horrible and just take one of the 50 or 100 ones for a decent restaurant, and just don't get it activated. He won't find out until they try to run it, I think.
This might be the most horrible idea I've ever had.
Then he might not understand that it was on purpose. Get one for 50, have dinner there yourself for around 45 and give him the card with the few residual bucks.