The humor on BSG is often more subtle, that is, they don't telegraph the joke, and if you aren't watching carefully or don't know the show, you may miss it.
It's often dry, wry and played with the volume turned down. It's "naturalistic", if you will. Written situationally, coincidentally.
It is rather unique, and works for the show.
I think that says it right there. Plus, Baltar and his antics have been good for some comic relief.