There are exceptions to every rule but.....
I tip generously
everytime I go out to eat. These folks make less than $2.50 an hour; most times their swamped with tables cause they're stupid boss can't hire any extra staff; most times they've got some real jerk-ass in the corner who thinks its fun to watch them jump for an extra buck.
Everybody has bad days. I think that by paying a little extra for the service maybe I make their day a little better. So, what's the harm?
I figure as long as they give me a cursory nod, fill up my glass once in a while and bring me my food, I don't need them to hold my hand while I eat or jump through hoops to get me an extra napkin. It seems to work too. I always get the table that I want and even though I don't ask for it, there's always a little extra attention paid to me by my waiter/waitress.
By tipping well I confident in the fact that my waiter/waitress isn't rubbing my silverware on her butt or blowing loogeys in my food.