A couple of points here.

I first learned how impressionable they are when I would tell my oldest one "time to put on your britches", just to aggravate my wife (she hates my hick talk). So, guess what she started telling her mom? We had to hit the reprogram switch on that one.

The Britney Spears, et al, affect is overstated. I have a 13 year, and she thinks those people are loser morons. I'm sure that has nothing to do with her pop saying that all the time.

Last - no one has said how important it is that they know theya re loved unconditionally. They do dumb things, and make you nuts - but they know they are loved, and that gives them a base to operate from. They have to hear that, hear it often, and know by your actions that you mean it.