Only if they were exceptionally rude though. I used to work at Subway and Burger King.
Don't get me wrong..I NEVER spit in anyone's food or dropped it on the floor. That's disgusting.
But be an asshole to me and I would screw up your food.
Examples: scream and cuss in the drive through and then tell us you want extra mayo? I drowned someone's burger in mayo for this. I'd be really shocked if she ate it. I know I wouldn't.
At Subway, if people were rude while I was making their sandwich I would squish their sandwich while I was wrapping and bagging it. No one ever noticed.
If people weren't assholes I made sure their food was fresh and made correctly..not slopped together. You didn't even have to go out of your way to be nice. Just don't be rude. That's my confession.