I tip less often than the average American because I’m from Australia. Also tipping is dehumanising, no one should have to dance for their supper.
I don’t understand why you would ever tip someone that hands you something as the only service. If they did less than that, it would be a police matter.
Waiters can also give you recommendations about the food. That said, they really shouldn‘t have to depend on tips.
I’m British and also very cheap, so…
10% is standard in my case.
In general, I tip 20% at restaurants and salons, food delivery services typically get a flat tip of $7 per order, maybe a few bucks if I’m picking up the food myself, and $1 per coffee or drink at a bar. If service is really good or really awful (ie, the server is rude), I adjust accordingly.
Edit: someone apparently doesn’t like what I do with my own money.
I tip 20%+ if I can. Most workers are underpaid. I want to support my fellow workers.
I also always tip 20% or more when I can. I think of it as solidarity. US workers are all vastly underpaid, especially waitstaff and anyone else they can get away with paying a “tipped wage” or whatever they call that lower minimum.
I do hate mandatory “service fees” or other auto-tips though, because usually the management pockets most of that so it’s just another way to steal workers’ earnings.