The YA & juvenile genres are no excuse for shit writing. Kids deserve high-quality reading material.

I can't stand incompetent head-hopping, either. When it's stylistically unmotivated, it's FAIL. There's a way to rock it, especially if a story deals with schizophrenia, or altered mental states, or a dimensional remove, or... you get the picture. There needs to be a reason for it, or the story will feel disconnected and random. (Unless that's the desired effect.)