I'm generally a 20% tipper ... 20%for fair to good service ... Less than fair service and I've left less ... Great service can get 30% tip.
Twice however I've left nothing. The first time we were halfway done with our entree and they made us move to another table because they needed the space for a party of 12, we were at a table for two, @*&! that, you don't make someone move in the middle of a meal, never went back there again.
The second time we went to a Mexican restaurant ( not Taco Hell) for one of my Daughters 10th birthday. She brought 3 of her friends, plus my other Daughter, wife and myself, we were seated and ordered drinks, received those and then ordered dinner. 45 minutes later I flagged down the waiter and asked what's taking so long ... he went into the kitchen, came back and said it'll be another 15 minutes ... 45 minutes later, again, still no food, I asked for the manager who came and promptly apologized and said it'll be out in 10 minutes ... half hour later still no food and I reamed this guys ass out in front of everyone ... 10 minutes later I got the food to go and wasn't charged ... Never went back.