I teach high schoolers, and sometimes you have to let kids be kids. Not everything has to be a teachable moment, and I'm sure that at some point she'll do something to "counteract" what you consider a waste.
Sometimes it really *is* about fitting in. In the scheme of things, Uggs and a $12 movie aren't a big deal. I'm sure that your kids got a great deal out of the mission trip you took them on to Nicaragua. She might not show it now, but she's learning. And she'll really blossom, especially in college. I've had a ton of students come back to me and let me know.
And, it could be "the" social event. Or a boy.
Honestly, my mom tried cramming down "everything's a teachable moment" and I really rebelled. Sometimes you have to trust your judgement in that you are raising a kid with good morals and values. I think I turned out ok.