On this song a couple decides that happiness comes in falling apart, not staying together. Thomas commented in publicity materials that the up-tempo beat belies the fact that "there's nothing happy about that one at all."
Who writes a song about a name they found in a phone book? That's just one of the everyday things these guys find to sing about. Anything in their field of vision or general scope of knowledge is fair game. If you cross paths with them, so are you.