Why does this happen?

So I don't remember if I talk to you about one of the guy that does karate with me that is a little bit younger than me. K has a really great smile, and i find him attractive! We've been vaguely flirting during classes, but nothing way obvious, because we are always surrounded by other persons.
So, a day last week, I was on my Facebook account, and he was on-line too. So i start teasing him, because he wasn't there for the last classes of this year, asking him if he was hidding. We talk a couple of minutes, when he ask me if I like partying, because him and a couple of friends when to a local dance club. And did i wanted to go with them. i wanted to go because it is my favorite club, and K seems to be my kind of guy. But they were going out on Saturday, and it was my nephew baptism on that day, so I told him no, and the reason.
And to make it worst? We only go out for supper after the ceremony! I knew it on Thursday or Friday that we wouldn't do much, but I was not able to reach him...
I hate it when this kind of stuff happen! I'm starting to think that I have the worst of luck with guy lately!