Until people pay to see you... You're there for their enjoyment... not yours. It's sad but true man. I've been to some frat parties where bands literally get ran off stage because all they want to do is play their original songs that no one has ever heard... Most people aren't into that. If they're at a party they want music they know... something they can sing along to and dance to.

But as was said... Try to mix in a few songs that you really enjoy playing. But don't lose the crowd because a lot of times crowds make snap judgements right away... and you'll have to do some major work to reel them back in. Plus.... I garauntee that when you have 50+ people singing a long with you... or moshing... or reacting to what you're playing... you're going to have the time of your life even if you're playing When I Come Around by Green Day