I stopped tipping for bad service. Like waiting too long to order. Thats my biggest pet peeve. I dont decrease tip if the food came out cook wrong, but I will if it has for example, tomatoes when I said no tomatoes. I think the waiter should look at the food before they bring it out. I can't stand when they dont apologize for a bad experience. Its like "well ef you too." I think waiters and mostly waitresses just expect a larger tip now they try less.