Your friends and family, and occasional acquaintances, make for great photo subjects. Until they stop letting you photograph them. Capturing images of people you know that surprise even them, or represent their personalities well, are intensely satisfying, while it lasts.
I credit my friend Rachel both for reinvigorating my interest in photography, and serving as an early model. Also, if she hadn't grown weary of serving as such, I might not have got into portfolio development. So thanks, Rachel!