I always thought cats rubbed against you, and kneaded their claws into you because they were using their scent glands to mark you. I've had cats practically drooling while doing it. Now every time my cat rubs his head against me I'm going to feel like he either thinks I'm dumb, or his mother....neither option sets well.
Side note, small dogs and big dogs think they're all the same size. That's why ankle biters stand up to everything, and huge dogs try to get on your lap.
Second side note, house cats have the biggest prey list of all cats (remember hearing this on Discovery channel I think). Like Lions eat Gazelle's, Hippo's (if they're lucky), and a few other things. House cats kill (not usually to eat) grasshoppers, mice, flies, lizards, beetles, birds, moles, rabbits, rats, ect, ect, ect.