Suntrust teller

I was behind an older gentleman in line at the bank. The teller gave him a receipt for his transaction. The gentleman asked him what that was for and the teller told him for his deposit. The gentleman/customer said that he was cashing the check - not depositing it. The teller said, "no, no, no .. you told me you wanted to deposit it... " Then he litterally threw his hands in the air and walked away from the window and huffed down to a co-worker to complain about the customer telling him the wrong thing. What? When he came back he huffed at the customer about having to redo the transaction. What happened to, "Oh, I'm sorry, I must have misunderstood you ... let me fix this..." Even if the customer did say that he wanted to deposit it (which I don't know because I didn't hear that part...) Perhaps the teller doesn't realize that the glass isn't a two way mirror and we can see and hear him.