Today I mistook a customer's outstretched arm for a hug invitation instead of a go-ahead-and-pass gesture. What's your embarrassing story of the day?

"I was working at a grocery store and a very obviously mentally handicapped man came in with who I'm assuming was a family member. As I was walking by him, he excitedly raised his hand and my brain jumped into Shit yeah! Hi-five time bitch! mode, so I hi-fived him. As my hand was coming down to meet his, the expression change on his face made it very obvious that he did not intend to hi-five me, and was actually just waving. But I had committed. Can't just let a hi-five die. So I slowly just brought my hand down to his and kind of just... slid/rubbed my hand across his with a nervous smile. You need to imagine the exchange here. He went from :D to D: as we just rubbed palms. It was all cool though, because after about three seconds of silence he perked back up and asked excitedly, "D'you wanna go ride firetrucks?!" I told him I couldn't because I just got off my break. tl dr couldn't ride firetrucks because I had to finish out my shift "