It's frustrating because everyone has different concepts of what a "good" tip is as well. I tip well now but it's mostly because I'm overcompensating for years of under tipping after getting advice from high school friends or cheap adults. However it's often just not clear enough what to give.

the percentage method is bad in my opinion. the most expensive cuisine typically hire more affluent staff and pay them more to begin with.

Personally I go with a $5 minimum, more if I am a bother or there for over an hour. Though, this makes me look like a jerk when people drag me to fancy restaurants, and a saint at coffee/fast food places.

Ultimately it doesn't matter how you tip unless you frequent the restaurant. Your service will be a result of the people who looked you and came in before.

So white, wealthy looking people will generally get better service by virtue of being white and wealthy looking. Doesn't matter if they skimp on the tip.

It's very racist and classist in practice.