#16: Sonic
“I found a cockroach in a Sonic burger. Well, half a cockroach. When I went inside and found the manager and showed him the chewed up pile of burger in the parking lot — with the half roach — he told me I put it there.” – shanlav

Have customer service people still not figured out that the customer is always right? Whenever a customer complains, especially about there being a gross creature in their food, surely the staff of the establishment should listen to the complaint, and act accordingly.