Some of those:
Friends: Because they mean the world to me and their art is aweome too.
Obvious: Because I love their work and I find others with common interests.

I am not the person to watch everyone willy nilly because that is not personal and there is no connection there. I hate those who watch everyone because half the time those folks have ulterior motives, getting free art, points, etc and that makes people in the community nuts. ><

I am very very picky with who I watch to begin with and I only watch 40 people. I just have to have a connection to watch someone. Present Company Included.