I've been living abroad for over half my life in a country where tipping is not the norm. At most you would round up. 19€ bill? Here's a 20, keep this change.
Going to the US soon to visit family and the whole idea of tipping makes me nervous. It seems there's a lot of discussion about getting rid of tipping, but I don't know how much has changed in this regard.
The system seems ridiculously unfair, and that extra expense in a country where everything is already so expensive really makes a difference.
So will AITA if I don't tip? Is it really my personal responsibility to make sure my server is paid enough?
American here. Here's the three common contexts for tipping. Everything else is something someone's trying to make a thing rather than actually a thing:
Restaurants: If someone is bringing food from the Kitchen to your table
Delivery: If someone's delivering food. Or they're personally delivering groceries.
Transportation: If someone's driving you personally. Like a Taxi.
Some say you should tip bathroom attendants. I've never even seen a bathroom attendant, but that seems like such a bizarre job to tip for, even by American standards.
Bartenders are a case that you've missed. A standard cash rate is $1 per drink. Bartenders have a lot of leeway when it comes to how quickly you're served, and how strong your drinks will be, so tipping well may be in your interest.