I don't really understand why they're friends.

Back in the day, I did a lot of coke. And I had a few really really really good friends. We had nothing in common, except that we loved long nights and blow. We would talk, walk, laugh, cry, reveal deepest secrets, spend hours and hours and hours talking. These are still some of my close friends today.

Do we have anything in common? Nope. Did we hang out much? Nope. But when we did it was always a great time, and even nights where it was just beer, or just weed, or completely sober, it was great. That happy, carefree, sharing time with someone who has seen you at your worst and knows your secrets so you aren't hesitant or self-conscious. It was a good time. Sometime's all it takes is a single common interest and reason to spend hours and days and nights together that makes a friendship superior.

I think that's how I look at their friendship. Normally they wouldn't be friends, but they enjoy each others company and have a good time and talk and talk and talk with ease.