Connotations of Movements

During my long time of watching lots of movies, I saw something that returned in most of the movies. It's actually a simple thing, and a really cool and useful one. The thing is that the place from where the characters come is closely related to their role in the movie. Role as in good or evil, that is.
When characters enter from the left of the screen, they are usually the good guys. When they enter from the right, they are usually the bad guys.
I think that this simple fact can be really useful, in two ways. Firstly, creating this pattern, or another one, can be really useful in making connotations and thus make the players feel differently for things, maybe even without knowing it.
Secondly, is the ability to break this pattern, thus making things that seemed certain much less certain and much more frightening. "What will s/he bring next? What pattern s/he will break next?" The surprise and shock of a pattern well built being broken can be really useful, and breaking that of characters? well...