Hmm, but if he eats my hand, it'll hurt and I'll be screaming a lot more, wouldn't I? And I'll get blood everywhere, and that's even more trouble for him to deal with! The easiest way to get somebody to stop bothering you is to give in and say hi, isn't it???

[ Just give into him... This is why people let him get away with things, probably, it's just easier in the long run. ]