Did I tell you I was I'm absentmindedly making fun of the grocery store cashier yesterday?
Why would you want to make fun of a cashier?
He was being rude and a total dickhead.
Even if the cashier was being rude, they may have had a very long day and they may be very tired. Be the better person and act kindly to other people, it's not right for you to make fun of people just because you can. We need to be more friendly and courteous to other people because we're slowly losing that trait as a society.
That sounds a little naive to me.
Having empathy doesn't necessarily make someone is naive. The cashier might have been rude, but that doesn't mean you have to act in kind. You don't know what that person has been going through.