bad behavior

I've been told that I have behavior expectations for people (including myself) and somehow I don't think that's a bad thing... So I have to ask myself today, what do you do when you see someone you care about doing really stupid things, hurting themselves and others as they carry on? I can't (or won't) pretend not to care, seems to be the answer. Okay, what about mildly not good things, like harmful habits that go underecognized? Isn't it your thing to do if you are a friend to make it an issue sometimes? Or is is more friend-like to just go about your business pretening things will have no negative result and let them figure it out the hard way, like how you learned when you decided to play the "I'm not touching you" game on car trips, where you're bored so your sister pays the price, gets upset, shit hits the fan and you announce, "I didn't do anything!", and suddenly you are in big trouble?

Isn't the real failure that you shoud have known, or that if you didn't, someone should have told you that what you were doing wasn't nice?

Maybe I'm biased or stubborn, or maybe even I am feeling guilty for making a big deal of things. However, I decided that I won't expect less of a friend or two just because they decided to ignore the consequences of past behavior, or the affects of those they proport to care about, or the dissappointment of friends such as myself, someone who wants people I care about to be the best people they can possibly be.

Is there a way to not lecture and not be apathetic? Is that what I should be trying to do?