There's one thing I never try to intentionally do at any restaurant, and that is tick off the people that handle my food. I once worked for guy that would inevitably send his food back because it wasn't up to his standard, which by the way was astronomical. I warned him that sooner or later someone in the kitchen would do something like spit in his food and he would be none the wiser. He never changed his ways, and I'm sure he ingested someone's DNA.

We've all see the videos and pics of employees committing various crimes on humanity by doing things to the food that is soon to be served to the unsuspecting public. With that being said, here are some of the most unsettling moments in fast-food history: