It always bothered me that in movies aliens always look more human than their own species and monsters always look more unnerving than human.

In my mind it should be the other way around. Monsters should be more human and aliens more unnerving.

Why?

Well, let me ask you this: if you were to catch prey in the wild would you rather stick out like a thumb or try to blend in?

Oh, this is Marina. The yandere.
Here's a older picture of what she's supposed to look like

Ooooor nevermind cause it's that old it's my even on this device!