Remember that the expressions and vocal patterns you are committing to film will become synecdoches... That means something little that stands in for something big. Your smile will stand in for all human happiness. Your tears will be a model for everyone else's sadness. ...You have a responsibility to the people who will repeat your lines, wink your winks, imitate your laughter without knowing they are imitating anything. This is the secret power that actors hold. It is almost like being a god. We create what it is to be human when we stand fifty feet tall on a silk screen.So you'd better be good at it, for God's sake.