Actually, there have been times when I felt not tipping at all was PERFECTLY acceptable.
Its not "eff you, work for free." Its "eff you, do your job." If you don't do anything, why should I pay you?
One specific time comes to mind. A few years ago, when I was still in Buffalo, I was visiting my family in Michigan. We went out to a buffet. There was about 9 of us, and most of the restaurant was PACKED because some high school was doing its 30th reunion dinner. OUR side of the restaurant was only moderately busy, and our waitress really only had two duties. Get us drinks, and bring us rolls. Not hard. We sat for 20 minutes before she ever came over to get our drink orders, and another 30 before we ever got our drinks! We could SEE her standing just inside the kitchen area, drinking something and chatting it up with some coworkers.
A very busy, very stressed waiter working the PACKED side of the restaurant had ot keep passing us to get drinks and rolls for HIS tables. ONce he came over and asked if our drink orders had been taken, and then snapped at our waitress to get her butt in gear, and when he passed us another 3 times with no result, he finally did it himself.
He was under no obligation to. Lord knows he was already way too busy. But he did. So when we left, my sister sought him out and gave him a LARGE tip, and left the waitress nothing.
She didn't do a damn thing. That's not poor service. That's NO service. That doesn't deserve to get rewarded with a tip. If that's the amount of work she's doing, her $2.65 an hour is overpayment.