Reminds me of a scene in Uncle Tom's Cabin. There's this black slave girl, named Topsy that does all sorts of bad stuff, and this white girl named Eva asks her why she does what she does, and the black girl responds something along the lines of "Hey, Not like people expect better of me" Just found it odd; Was never expecting to be reminded of that scene today, or this year, or ever. The human brain is really quite interesting. Eva shows Topsy some love and forgiveness, basically treating her like a human being, and Topsy turns for the better. Responding to poor tipping with poor service really doesn't seem like a good idea.This causes a feedback loop of a garunteed bad tip and terrible service for the next group of Black patrons who will in turn not tip for shitty service.
If it was just Topsy waiting on just Eva every single meal that would be easy to see. But when things get more transactional and less.. relationship-al there's less incentive to turn the other cheek. Even if you were nice to them and they started tipping better, somebody else benefits. It's hard to think "what goes around comes around" at such times, I imagine. That's why we have the tragedy of the commons.
Every service exchange is about relationship, not realizing it is part of the problem. If you can build that relationship the first time maybe they come back. The bar I work at is in an area of town that has been heavily gentrified over the last ten years. When the place opened it wasn't uncommon for blacks to scream obscenities at the patrons through the large bay doors of the place, after six years we have a pretty decent group of black regulars. Each of the black patrons was hard won with handshakes, remembering names and drinks and just getting to know each other. The perception that each transaction is just a one time game is where the tragedy comes in and people fail to connect.