Amen to that. Cat photos get a bad rap because there are so many puke-inducing ones out there, but I think they're a good exercise for the photographer anyway; if you can get a good portrait of a fast-moving, intelligent, perverse animal that can teleport to get away from you, you're doing OK.
Toddlers, of course, add to that same collection of tools the desire to walk up and grab the camera while you're composing. I've watched many a nice picture dissolve into a blur of grasping fingers before I was ready to shoot. (They don't teleport quite as well as the cats, though.)
-NT