Those that mock and become stupid at restaurant help, at the drive through or whatever, are really stupid. Never piss off those preparing your food. That’s just asking for it.
I personally just stay away from public eating places whenever possible.
USAto***y several years back had a story about this. They said something like 35% of the Chef's who had to recook steaks admitting tampering with the food.(dropping it on the floor/spitting etc). The chef's did this because they look upon themselves as artist and when someone is saying their food is not right they get offended.
I also know a highway patrolman who will only at eat places where he can auctually watch the staff make the food. Like Subway/Quiznos etc