A fair tip is between 20% of the pre-tax and 15% of the post tax.
Rotten service deserves no tip (nor a return visit to the resaturant).
I usually tip to the next even dollar over 20% (including tax). I do, however, expect the server to actually look at the plate to see if I got what I ordered.
It is simply amazing how often they screw up the order. I can't remember the last time I got exactly what I ordered. Is it really so complicated to leave the croutons off the salad? Is putting the dressing on the side a complex task?
I wonder how many of these celebrities got crappy service and gave lousy tips for lousy service.
My regular practice when I receive lousy service is to tip 15% and never go back. If the manager isn't smart enough to notice the bad service, there's no point in me telling him.
And don't forget to "toke" the dealers at the Casino either. A couple of months back, I'm playing Hold 'Em at the Mandalay Bay. This guy across from me is raking chips from a number of suck-outs against a better players (me included), and not tipping once. I'm talking pots of over thousand dollars, which would typically get the dealer at least a 25 chip.
Well, an hour later the poker gods finally catch up with the guy, and he starts hemorraging. His stack is going down fast. Finally, he's all-in against a rock sitting next to me. Showdown, and the guy sitting next to me turns over a flush. The other guy had a set of kings... or so he thought. He shows his hand, but he also has a flush as well (king high, higher than the rock's). Nobody at the table says anything, including the dealer, as the guy mucked his cards and threw them away.
When he left the table, the dealer just smiled. The guy who won the pot with the weaker flush tossed the dealer 50 dollars.
Had that moron been tipping, the dealer would have encouraged him to put his cards on the table, rather than muck them, and he'd have raked a nice pot.
So, when the crooks at city hall decide to grab MORE of your money, waitresses gets more too, eh?