Hello everyone,
Stagefright would keep you from doing it, but you didn't say anything about quitting. I think it's just a matter of not being comfortable with everything you're playing. As Neal said there many added factors in a performance, so you may not remember everything you want to play. Hundreds of times I've thought about a lick I wish I'd played in a song, and just make a mental note to use it next time.

Another thing that makes it easier is knowing several ways to play the same notes. Having plenty of riffs will make it easier too, then you won't feel like you've used every trick you have. You're just a little nervous, this will change as you get more comfortable being on stage. It's not as hard to play what you want to play, when you're not worried about playing what you know.

Have a great weekend, and hit the stage everytime you can.