I have never done it before... left a bad tip for a waitress. Here's how I usually do tipping:

I start at 20% (25% for breakfast), then work down (or up if the server is fantastic). From that 20% I work my way down based on some basic factors;

* Attitude. You don't have to be overly (fake) nice, but at least be pleasant. Don't rush me, don't look like I'm putting you out. Just smile and be nice.

* Drink refills. This is especially important for breakfasts and my coffee. The longer my cup is empty, the lower the tip can get. I even make it easy and put empty cups near the edge of the table to make it as obvious as I can.

* The "is everything OK?" check. Don't ask me how everything is 30 seconds after you put it down. And, don't ask when I'm done with the meal. After giving food, about 5 minutes later is the right time to ask, since a drink refill may be needed.

That's really about it. Those are some pretty basic wait staff things, and not hard to get a good tip. Usually, I end up leaving between 15 and 20%, which I think is fair-to-good tipping. But, not on Saturday.

We went to a Mexican place we'd been to once before. One thing that lacks up here is a good Mexican joint.. or at least we haven't found one yet. But, this place isn't bad. Things started fine, and the waitress was starting off ok. Then, we ran out of chips. No waitress. Suzy put the basket in a more obvious place... no new chips came. Finally, the hostess saw and brought us more. You need those chips while waiting, after all. Then, the food came. I let it slide that I got Tobasco when I asked for hot sauce. Everyone does this, and I have yet to be to a Mexican place which actually has hot sauce and not just pepper sauce that's not hot. Anyways... Suzy asked that they put mole (sp?) sauce on her meal. When she got it, it was spicy. So spicy to her that she couldn't even eat it. She took the sauce off, but was too spicy. The waitress never said that their mole sauce was spicy and Suzy has had plenty of mole, and none has been spicy.

5 minutes.. 6 minutes.. 7 minutes.. 10 minutes... finally, the waitress comes by. Suzy said the dish was too spicy and the waitress said "I can take it back and..." you'd think here she'd say she would talk to the cook, or replace it.. "clean it off for you." That's right.. she would somehow clean it off better than Suzy did. Maybe run it under water? Lick it dry? Suzy said 'no', and she offered to bring some cheese sauce to help drown out the heat that Suzy couldn't handle. bzzzzzt.. wrong answer toots. If someone doesn't like the food, you take it back. Especially, if it has come at a spice level not expected, noted or explained. Of course, I was almost done with my meal since it had been 10 minutes already. She asks Suzy if she'd like a drink refill, she says 'yes' and the lady walks away. I glance at my ice-filled soda cup wondering why I wasn't asked. But, she'd be a good waitress and bring me a refill anyways, right? Being preemptive of my thirst, right? bzzzzzzt. No refill for me (and there would be no other chance that night).

She gave Suzy the cheese, and went away. She really didn't seem to care, not even fake care, about the fact that Suzy couldn't eat her meal. The cheese didn't help, and Suzy pushed the plate away. About 10 more minutes after we were both finished eating, a different waitress (who was stationed at a table next to us) came and cleared our table. Our waitress was nowhere to be found. Not even a follow-up visit asking if the cheese helped.. or if I was thirsty. She finally came back a few minutes later asking if we wanted dessert. We did, but they were out of what we wanted, so we didn't. She then left the check.. with the full price of the uneatable meal on it.

Bill: $38.78... cash left on table: $41. That's the absolute worse tip I have ever left and it was completely deserved. It may not come across, but it was. She was terrible, vanishing, uncaring and unattentive.