And while I might bemoan the spread of the tipping economy to all interactions, I still think that in America, you can tell a lot about someone from how they tip at a restaurant. Not everything, but some things.
That's tricky though as there are generational and cultural considerations to take into account.
Regardless, of what I think the tipping culture
should be in the US, I try to act appropriately for the world I actually live in. At restaurants I tip 20%. My wife has given me hard time, thinking its too much, but she comes from a non-tipping culture and finds the whole American tipping culture confusing and annoying.
To be fair, outside of restaurant tipping, it confusing many Americans. I was called out by a colleague early in my career for how I tipped cleaning staff at hotels. I would just tip at the end of the stay, instead of smaller amounts daily. Because the cleaning staff may change from day to day, he said I was screwing over some staff and giving the others a windfall.
My parents still think 15% is the appropriate amount because that is what was the norm when they came of age.
Then there are people who are great and kind people but just have some moral aversion to tipping, or feel like tipping culture has gotten out of hand, and that influences their tipping decisions.
Then there are various racial stereotypes that further complicate things. When I was living in Hawaii many restaurants had separate menus with different prices for Asian tourists. On the mainland, some groups might not get the same service because they are seen as being poor tippers.
Tipping is one of those cultural flashpoints that makes me careful to be too judgemental about it.