I guess some of it is cultural rather than rational, but is tipping wait staff so much different? If you go to an expensive restaurant and pay double for the sa

I guess some of it is cultural rather than rational, but is tipping wait staff so much different? If you go to an expensive restaurant and pay double for the same food as in a cheaper one, then what exactly are you paying for, and in any case why is the tip a percentage (vs fixed amount, as is normal in the UK) such that the wait staff in the more expensive place get more? Whether rational or not, I'm personally fine tipping where the worker is making a low wage, and have spent time personally attending to me. Part of it is thinking that they'll appreciate it more than I will miss it.