(Show a pair of well-worn hiking boots. )
These old boots have taken me over a lot of miles of trail. They're really comfortable. Whoever coined the expression, "as comfortable as an old shoe," must have been talking about these old boots.
But once, a long time ago, they were brand new and stiff as a board. Oh, I softened them up with some polish and saddle soap, but mostly I broke them in by using them.
One step at a time - that's the way good boots become good friends.
Good habits are like that, too. The first time you do something hard that you know is right, you may feel as uncomfortable as a new boot. For instance, maybe a friend suggests that the two of you steal the answers to a quiz from the teacher's desk. Maybe that doesn't seem too bad -
bad you know it's wrong and perhaps you hesitate. But you refuse to do it, even though your friend calls you chicken.
Nobody likes to be called chicken but you'll be secretly glad you refused. And I'm sure you'll find it easier the next time, because, like these boots, good habits become more comfortable each time they're used.