Because he's a pain in the neck.
nervous glance at dog Dog: Frank, we've been over this. I like you as a friend
Crumbs!
Its a life of pain
One causes a lot of pain and makes a constant high pitched whine. The other is a useful piece of medical equipment.
Head.
Not enough cement EDIT: Okay thanks for pointing out that I messed up the wording but the joke is supposed to be the funny part
His fang club.
Dracula.