Movie myths busted or myth busters

[crosspatch]

Well, since having read about a lot of strange situations and behaviour of the protagonist/antagonists, unexplainable even by the most well-meaning fans, I decided to start this thread if it's OK.
We all know air is breathable whenever you go and gravity equally suitable for all creatures in the movie /can't imagine any good fighting scenes in space suits/ and ... the evil creature always turns out alive to provide for a sequel.
So, are there any interesting/stupid/not abiding to the laws of physics things, situations, activities, reactions you noticed and want to talk about?
Something like: "don't do that at home, it's not real life!" warning

[Mr.Black97]

what?

[E-Stalin [Orthrus]]

As a rule of thumb, if it's a movie: everything.