Cooking an order of mussels at lunch reminded me of a grumpy old man at dinner several years ago.
He came in solo for dinner and ordered an appetizer of mussels for his dinner. Maybe he wasn't hungry; I'm thinking he was looking for an inexpensive (read "free") meal because a minute or two into his mussels, he summoned the server to the table to complain that several of the shells contained no mussels at all and that he didn't want to pay for them, oblivious (more than likely intentionally so) that said mussels had fallen out of the shells to the bottom of the bowl.
I ended up comping him for the mussels (and the three loaves of bread) that he ate knowing that he'd never come back and that he'd go pester some other restaurant. And sure enough, we've never seen him since. I still chuckle about the old guy from time to time when I remember him. He's the kind of customer that makes for a good story at our Christmas party.