It's mainly about working hard and proving to people you're serious about it and stretching yourself and learning. The mistake a lot of actors make particularly young ones is allowing themselves to feel that they're the finished articles the bee's knees and it's not true.
That's a big deal for kids when they come into the kitchen and the teacher is drinking coffee with mom. They react differently on the next day when you say: 'Sit down and shut-up!'
