Assessing the people in your life?

I just heard Dr. Drew and a women on TV talking about assessing the people in your life, I thought this was an interesting concept. They stated to look at the people in your life and  ask questions, are they healthy for me? Do they bring something positive into my life? I found this very interesting as I have been doing something similar. I have found that when I surround myself with negative people or people who aren't "good" for me, it has a huge negative impact on my life as a whole. The reverse is also true.

So when I thought of who was good for me, who was healthy in my life it made me think of what kind of life I wanted and what kind of person I wanted to be. Big questions. It also made me think of what kind of friend I was, was I healthy for others, did I bring something positive to other peoples lives? 

So, I believe, that I should not only look at people I have in my life but also look at myself and ask those hard questions and decide, am I the type of friend that others should have in their lives?