One day my BF was at the seafood counter selling shrimp they had on sale. They had tons of shrimp, and needed to sell it. In comes "evil customer" and he butts up to the front of the line and starts yelling, loudly, about how the shrimp are bad, they smell bad, they taste bad, they won't peel right. BF sees other customers in line getting ready to leave so he asks bad customer if he could please have the shrimp back. Customer tosses them on the counter. BF looks into the bag and says in a loud, but calm voice:
"Sir, you're supposed to cook them before you eat them".
He then offered to steam aforementioned shrimp for evil customer. Evil customer treated him with much greater respect after that incident.
Sometimes bad service, sometimes bad customers.