Him: Oh, hello, smart girl!
Me: (smiling because I'm nice to him even if it's vaguely odd) Hello.
Him: (as he takes the ticket) You're so smart and cute. Did you know that?
Me: No, but thank you.
Him: It takes a smart man to see it!
Me: .... Thank you.
There is an exchange about the $20 I give him (no, didn't have anything smaller), and then he starts giving me my change, but stops dead after the bills. After a second, I realize he's waiting for me to perform an amazing mental feat and calculate the change in my head, then tell him. So I do.
Him: So smart! And so cute! You have a good day!
Me: Yes, you too.
I think he got the idea I'm some sort of mental math dynamo because of the last time, when he got confused and I asked very politely for my nickel, which I knew I had coming because, well, I AM a mental math dynamo. At least when it comes to getting correct change. ^_-