Contrary to popular culture, there are a lot of people out there that want to gain weight. I was one of those people. I'd been skinny all my life. I was always the shortest and smallest guy in class. I wasn't very outgoing, but I was very smart. Talk about hard times in school and your classic nerd.
Then I found the joys of muscle building that changed my life. Now, I have the knowledge to put on as much weight as I want. I'm no longer at the mercy of my genes, but that doesn't mean it's easy.