It's not a tip, it's a bribe. You can tell people perceive it as a bribe because they speculate about what would happen if you don't 'tip'. In the most tame spe

It's not a tip, it's a bribe. You can tell people perceive it as a bribe because they speculate about what would happen if you don't 'tip'. In the most tame speculation you get people like the parent who expect they'll get better service for tipping ahead (implicitly, you'll get worse service if you don't). On the other extreme are fears about employees doing something awful to your food. Neither tipping or bribing is healthy because both are built on a social contract that can be voided by one party without much consequence—the only difference is which party is in a position to void the contract after reaping the benefits.