Are What lesson am I supposed to teach?

I am not big on religion but I believe in god, praying, the bible, and some other things that have to do with religion. It's not the same thing but that's not the point of this post.

   the point of this post ,is that I believe that god eventually weaves the people who are not suppose to be in our lives out. I was thinking that god weaves people out of my life who are not good for me. what if I have been a person that god has weaved out of someone's life and I just think that they were bad for me? if that could be the case, how could I possibly know if I'm bad for someone?
   I realize that sometimes I can tell if I am bad for someone but that have been extreme cases and I can obviously notice it.

But think about that. People are put in our lives to only be a lesson. If that is the case, we have been put in some people's lives to be a lesson. I know some people have realized that, but that has never occurred to me. I don't know why it hasn't. To me that is some deep stuff.