Why does this crap always happen?

So I've never had much luck with girls. I've taken to trying to meet a few on Plenty of Fish, and started talking to one who messaged me first. I thought she seemed pretty nice, and we made arrangements to go out today. When I got to where we were supposed to meet, she sent me a text saying she saw me and I looked around for her for almost an hour, and got another message saying she left, so I left to go home and got another one saying to come back. I've been played around before, so I just up and left still anyways, but why the hell must girls be so condescending and rude like that? Why does the nice guy always get ****** over?