I was just at a convenience store buying some food. Their was a cute girl behind the counter who was smiling at me, and she seemed very friendly in our typical polite customer - cashier conversation. I really felt like I should have said something more because she seemed interested in me, but I had no idea what to say. So i said 'have a good day' and kicked myself all the way home haha. Does anyone have any suggestions for the next time something like this happens?