Even better when the customer just plain orders the wrong thing. I have a vivid memory of my pregnant wife and I at breakfast one morning, and she ordered apple juice. When the waiter brought apple juice she said she’d ordered orange, and when the waitress looked confused, I had to remind my wife she’d ordered apple. Total brain fart on her part (pregnancy brain seems to be a very real thing). Waitress didn’t care, especially after we laughed it off, and brought orange. But I know I’ve undoubtedly done the same thing, so I’m patient with mixups.