Why do singers always want to become actors and actors always want to become singers?

I don't know, but just remember that it isn't always a bad thing. One of my new favorite bands has a lead singer and songwriter who was an actress, but she's much better in music than she was on screen.

Also, I just saw "A Mighty Wind" last night, and most of them are great musicians as well. I liked Eugene Levy and Catherine O'Hara's duets.