How useless are you at telling a girl likes you?

Quick anecdote. I was just in a supermarket and was queueing for cigarettes. The counter I was waiting at does both cigarettes and lottery. Another cashier came along and opened up his till and just called over to ask if anyone just wants cigarettes and no lottery. Being next in the queue I headed over. There was a girl in the queue too, very cute, who started over as well. As she was down in the queue, she realised she was pushing but laughed it off (no big deal). So I'm waiting for the guy to ring me up and she walks over. Exchange a couple of pleasantries and she's all smiles and we're chatty ish. I leave, get in my car drive home. I did happen to look back as I left and thought I saw a bit of an expectant sort of surprised look and I think it's only just dawned on me she wanted me to chat. Ooops.
So how useless are you? What are your missed opportunities? Entertain me while I'm on my own eating my salmon salad and coffee.


Source.