PSA on tipping:
For anyone visiting the US right now, we do tip at restaurants. It is customary to do so, but it does vary depending on the place.
The only places that you should expect to tip fully on is at full service dine in locations.
If they seat you, take your order, serve you, etc the standard tip is 15%. It's not 18%, it's not 20%, it's 15%
That being said, that is for average service. If they go above and beyond, I will tip far more than 15%. 20-30% is not out of the ordinary for me, if they are giving amazing service.
If they give me bad service, I will tip less than 15%. Rarely less than 10% but I have left a $2 tip on a $90 meal because the waitress was genuinely rude and caused us to have a less than stellar dinner.
Now if you order at a kiosk or front service desk, get your own drinks, etc, 15% is grossly overkill. Do not feel obligated to do so. Generally speaking, I leave a few bucks for bringing my food and cleaning, but that's all they are doing.
Coffee shops, ice cream shops, etc do not necessitate tips, even though the staff will ask for them, sometimes very passive aggressively. Only tip if you want to there, generally because the staff proved they deserve it.