Do you give a well-liked restaurant a pass after a bad meal?

Or do you never go back there again? Had lunch with a friend and the service was bad and the food bland. She’s a vegetarian and thought there was meat in her dish but the waitress said it was an herb – and I think the waitress was right. In the past, I have enjoyed it there very much. Should I give them a pass for the one bad time or cross it off the list? WWJD?