Acting differently from the person you're interested in?

[nogameyet]

I'm sure we all know this feeling. When you like someone you act differently around them. You may come across stiffer, more serious, less fun, which isn't usually who we are. I'm only like that with ther person I like. I wonder if there are techniques or things we can do to change that, or am I just screwed? Would love to know what everyone else does to overcome this.