So Not Smooth

I stop by a fast food place after work for a fruit smoothie, which is currently being advertised for $1. I order and hand the cashier a $5 bill with change to cover the tax. He gives me $2 back and walks away. I leave it on the counter while I wait for him to come back.

Me: “Those smoothies are a dollar, right?”

Cashier: “Yeah.”

Me: “Well, I gave you five dollars.”

I’m trying to give him a chance to realize his mistake.

Cashier: “Yeah.”

Me: “And you gave me two dollars.”

I hold up the coin he gave me.

Cashier: “Yeah.”

Me: “So…?”

He just gives me a blank look.

Me: “I’m going to need another two dollars.”

Cashier: “Okay.”

He opened the till and gave me my two dollars. I have no idea if he was just dense, trying to scam me, or what, but it was definitely odd having to walk a twenty-something dude through kindergarten-level math.