311 - Beautiful Disaster Lyrics Meaning

He's talking about struggling to stay positive and avoid just walking away bitter but he has no other choice. The person he's done dealing with seems to be a selfishly free-spirited person that takes life as it comes, lives to enjoy life and he likes the idea. However, she does soon start going too far and out of control as her fun-loving nature knows no bounds. She seems to be completely insensitive to the well-being of anyone (including herself) in search for more to life, so he's gotta just get himself away from such a negative vibe (and being such a positive-minded guy and group as a whole, I wouldn't be surprised if this was strongly based on someone in real-life).

But I could be wrong, I usually am :p