As the lead of a movie, you really set the tone off-camera as well, and that's a really big responsibility.
It's surprising how many persons go through life without ever recognizing that their feelings toward other people are largely determined by their feelings toward themselves, and if you're not comfortable within yourself, you can't be comfortable with others.
I often get sent scripts about little men in big situations. There's a comic element to it, which is forces stacked against this little guy, and how is he going to defeat them?