I've been fortunate that I haven't had a lot of bad experiences that really stick out, but this happened a couple of months ago, and just felt like sharing.
I was in Illinois for an audition at a small university. My father lives in the town where the school is, and after the audition, he, my older sister who also lives in the area, and I went to a newish Mexican Restaurant by his house (I had been there once before on a previous visit). I love Mexican food, but I'm a fairly picky eater, and don't usually go much beyond ordering Cheese Enchiladas or Tacos, with the occasional taco salad or nachos in restaurants.
We order, and I get my usual Cheese Enchiladas. A little while later, the waiter brings out our orders, and he brings me Chicken Enchiladas. Okay, no big deal. Mistakes happen. I'm usually pretty easy going about it, as long as I get what I actually ordered. When we informed him of the mistake he almost seemed to deny that it was wrong, which of course it was, my sister and father had heard what I said.
A little while later he brings me out another plate, plops the thing on the table (not exactly gently, either) and leaves.
On it are the three cheese enchiladas, covered in ranchera sauce and cheese, and the outer edges are burned and GLUED to the plate. It was nearly impossible to get the bottom part of the enchilada up off the plate, and the only part at all that was really edible was part of the middle enchilada that was in the middle of the plate.
My father said that that had happened before, and it was on purpose. They were just lucky that I wasn't paying and wasn't in charge of the tip... and they were the ones that got stuck trying to pry that off the plate.
I'm really going to miss the Mexican/ Tex Mex down here in Texas when I move back up there.