A bigger question is why can he survive being shot, several times, suffering all kinds of abuse and then falling out the window but still getting up and walking away? And that is just in the first movie!
My guess is that Michael knows he would not be half as scary without the mask. As for why the filmmakers did it, this about it this way. A movie with a killer running around is a thriller, put a creepy mask on him and it is a horror movie, end of story, masks are scary.
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@}->-If you are ever attacked by vampires, held hostage by aliens, haunted by angry ghosts, put on a zombie's menu, stalked by an undying killer or in other ways find yourself in a horror movie situation, never, ever go near the bathroom!-<-{@
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