Tipping at the buffet?

[Zebra]

Today I took my son to a popular local Chinese buffet. Different permutations of our family have been there probably at least 30 times. I have never left a tip because most people tell me it's just not necessary at a buffet. They bring you your drinks and clean the table at the end and that's it. Usually I pay the owner who also plays a server sometimes. He has always been very jovial and has never said a word about me not tipping. Today the waitress, also Chinese, had me pay her since the owner was busy, so I met her at the register and gave her my card. Just like any other time I didn't leave a tip. When the waitress got her copy of the receipt she glanced at it in disbelief and started asking me if everything was okay and I said sure, it was fine. She followed me back to the table as I went to get my son, and was still asking in disbelief if everything was okay, and I assured her yes it was. At that point I realized what she was getting at but since I had already signed the bill I kept my composure and just bit her good night and walked out but I could tell she was borderline fuming about it. Now, interestingly enough...sometime during my meal...the buffet switched from the lunch menu to the dinner menu unbeknownst to me. So when I filled up my plate for the last time the waitress came over and informed me that I had just taken food that was on the dinner menu and told me she was going to adjust my bill to reflect it! Our bill with tax ended up being like $8 more than it had been before. If it had not been for that fact, I might have felt kind of bad for her, and second-guessed that maybe I should have been tipping there all along after all. I'm now confused as to whether I made a mistake or this girl was just being greedy or what. I immediately googled the topic when I got out to the car, and found that many people will tip about half the standard rate of 15% which would be about 7%... but also that many people don't tip at all at buffets. So I'm really on the fence about what to feel in this situation. This is the first time any server has ever called me out for this at a buffet, or even seemed remotely upset about it. I'm curious how other people would feel in this situation and whether or not they tip at buffets, and if so how much.

Thanks!

i do not tip at a buffet!

 

[whitehall]

Is it about the Chinese? They prepare the food, serve you drinks and offer you a clean table. Tip them a couple of bucks for God's sake you cheap bastard.