In my university days I worked in hospitality. First as a waiter and then as a bartender. Where I worked we had quite a few regulars. Some tipped, and some didn't. Like it or not, those that tipped always got better/quicker service from myself and the other people I worked with. I was never rude or anything, but say two people came up to the bar at the same time, one tips and one doesn't, I of course would always serve the person who tips first. We would even point out to the new staff who tipped (as well as what they liked etc) and who didn't.
Now, of course I don't condone tipping when service is horrible (and if I don't tip, I will always endeavour to explain why). But if you've had a decent time, then why no show your appreciation? In a sense, tipping is like recognition. Here's a few bucks to say thanks. Is it really going to break the bank?
Also, I cringe when I hear someone getting obnoxiously pissed off with a waiter/waitress etc. There was this one place where this yuppie punk was verbally laying into a waitress for some stupid reason at the table next to me (I can't remember what it was, only that it was incredibly stupid) and so I put him in his place quick smart. He was feeling pretty sheepish when I was done with him. On the flip side, the waitress was basically falling over herself making sure we had everything we wanted. Lambasting someone because of bad service is not going to help things. It's going to do the opposite. They're not going to think "Oh, that guy is pissed off so I should do a better job". They're going to think "Jerk! Who the hell does he think he is?!". There are ways of dealing with people, and unfortunately, some people just don't know how. Bar them throwing food at you or something along those lines, there should be no reason to yell at someone or abuse them. Would they come into your office and yell at you? No. So why are you going to theirs and yelling at them? If your food is a little cold, kindly point it out and ask for it to be heated up. If you're given the wrong thing, nicely point it out or better yet (and I sometimes do this) mention that it's not what you ordered but it looks good and you'll have it anyway. If service is a little slow, make a joke out it. Chances are, it's probably pretty busy and they're being asked a million things at once. A little joke will relax the person who is serving you and you will be treated much better than everyone else. Basically, if you act like an a**hole, you will be treated like one!
One last thing. I took this cue from an uncle of mine. Whenever I go out with someone important (business wise, or even dates with the wife), I find out who will be looking after us. Then I approach him or her, hand over a certain amount of money (here I give anywhere between €10 and €50 depending on the location, the importance, and how much I plan on spending) and ask him or her to really look after us for the evening. I also mention that there will be more at the end and how much depends on the service. When I've done that, I have never ever received bad service. Whoever I'm with (except the wife, because she knows now) always comments on the excellent service. I just smile.
Sorry for the long post, but this thread brought back a lot of memories.