Wanted to smack the kid!

I'm normally an easy going person. Today I went to Graeter's for ice cream. After ordering my ice cream a young male worker ask's me what a MOPAR is. I didn't think at the time that I had on my FABO shirt 5 Things. My first reaction was to stare at this young man. Then I wanted to reach out across the counter and smack him! But instead I asked if he was serious. I then ,as politely as I could, explained it's a name given to Chrysler products. The origin of which was when the had replacement parts called Motor Parts. Then it got shortened to MoPar.
I still think I should have smacked him first then explained.