I was fortunate enough to have a teacher in high school who incorporated a lot of practical life lessons while also bringing up issues on rape, equality, bullying, etc. all through the lens of a health class. He was unanimously liked by students from all walks of life, and I think anyone who's taken any of his classes is a better person because of it. 

You really hit the nail on the head in pointing out that teachers have every opportunity to teach more than just their subject. Under the tutelage of a caring educator, students become more likely to be caring themselves.