How do you know when to butt out of your friends' personal decisions and when you have the right to interfere? There are arguments for both sides. On the one hand, we aren't kids anymore. We're at a point in our lives when it can be assumed that any and all decisions are made with care and consciousness, and so we need to leave others to endure the consequences of their actions - good and bad. The whole "let people learn from their mistakes" approach. 

On the other hand, we also aren't necessarily the smartest. In many cases, people from the outside looking in have a much more streamlined, unbiased idea of what is happening and what is the best course of action to proceed. What kind of people would we be to stand idle while we watch a loved one walk straight into what is obviously (to us, anyway) meant to end badly? This is the "friends don't let friends ________" mentality, and also a mindset that I liken to the well-known philosophy "there are two types of people: people who do bad things and people who see bad things being done and don't do anything about it".

Maybe there is no answer to the question of which approach to better. Maybe different circumstances require different levels of interference, if any. I guess it's just hard to stay away sometimes when you're so used to being proactive and outspoken. What is logical to me is either not logical, not practical, or just not wanted by other people, and it's my responsibility to accept that. It's hard though, when you see your friends prioritizing the wrong things, or making risky or unwise decisions, or wasting their time with people who don't deserve them.

Then again, I also should try to remember that the concept of "wasting time" is entirely subjective. So even as I do my best to see the world arbitrarily, it's okay that other people look through different eyes. Someday soon, I think, I will be at the opposite end anyway.