This should be common sense: Don't mess with the people who serve you food. And honestly, treat them as well as you can manage. Tip well, say thank you, and be a pleasant person to experience, and you'll get a pleasant experience in return. And also, it's just generally better as a human being not to be a jerk.
A recent Reddit thread called "What’s the most malicious thing you have done to get back at a customer?" provided plenty of examples of what happens when you break this simple rule. Stories poured in from restaurants and bars, even a snowcone stand, but they all had the same moral: Stop being a jerk.
The thread started with the original poster sharing an anecdote about letting kids spill ice cream all over themselves, and it only got worse from there. Some are cruel, some are petty, some are malicious, but all of them are satisfying as only revenge stories can be.