"You're the one who said you'd never leave."

I feel like I have a lot to talk about, and that maybe I just don't know where/how to start...
There are people that come into our lives that are just normal people. Every once in a while though a person or two will enter your life who is extraordinary.
In the past year I have been lucky enough to make friendships with a few of these people. Sometimes we never really know what kind of impact we've made on another person's life until they tell us. The smallest things can make such a difference in the lives of others.
I wonder what kind of affect I have on the lives around me.
I hope I'm the kind of friend that my friends need me to be. I hope that I can offer them something in their lives that no one else can. Is it selfish to want to be a great friend?
One of my friends that I've known since we were babies is coming home soon. He's been serving a mission for The Church of Jesus Christ of Latter-Day Saints for the past two years. Before he left we didn't really talk. That's weird because when we were little we spent a lot of time together. I'm really excited for him to come home.
What are the rules of friendship?
I mean obviously there's the "do unto others..." rule.
I just kind of wonder if there's more to it.