I got fired from McDonald's because I repeated my brothers order as "1 McCum sandwich" and my boss overheard me.
Why did you have to do that?
I was just trying to mess with him.
Since you were on the clock it seems your employer was within reason to fire you. It is not okay to say things inappropriate like that when you are at work.
I didn't think it was a big deal when I said it.
You never know who is going to hear it. I mean you didn't expect your boss to hear it, what if some young customer heard it as well?