I've seen too many people do too many gross things at buffets to ever patronize one again. That was probably 30 years ago.
Before my buffet boycott began, I had a friend who raved about a nearby Chinese buffet so I joined him for dinner there one evening. There was carpet on the floor (never a good sign) that was stained and had areas of spilled food. I commented to my pal "You know, they say in some restaurants you could eat off the floor. In this case, there's enough food and other junk embedded in the the carpet that you could truly eat off the floor."
A few minutes later I saw a roach crawl up the wall.