Once in a while I will watch a movie and find it bad. Then I will think why it was bad, because in some cases the concept, the actors or quality of the film was good. Then I will stumble upon what I have begun to call the "rules" of film. Here an example.
The other day I saw a movie called Walled in. It's a horror/thriller starring Mischa Barton who is probably more known for being in the tv series O.C. - or welcome to the o.c. bitch - as I like to call it. I didn't like this movie. And here is what rule it broke that made me not like it -
Don't derail from a set direction.
The movie is about a demolition company rep (Barton) who is sent to this creepy apartment building in the middle of nowhere to begin preparations for it's destruction. The building has a history as many bodies had been discovered within its walls and the architect was supposedly a genius. We later find out that the architect was obsessed with mythology and ancient cults and the idea is planted that he may have been up to some creepy things. In the building's entrance there is a strange mark on the wall and overall you could imagine something bad going on in that building. When Barton stays in one of the apartments during her assignments she has spooky nightmares and hears a dead girl's voice from within the walls. Many times she hears or sees something ghost-like.
Now all this told me it was going to be about the architect and some kind of unholy rituals connected with the building as well as a healthy dose of ghosts. I was so sure that in the end she would blow up the building and free the trapped souls that had been captured there by the evil architect. pustekuchen (as the German might say).
We find out, yes the architect killed the people who were found walled in and he did so believing that would make the building stronger (?) but there are no ghosts, and there is nothing supernatural going on.... in fact, the evil architect has been trapped in the building himself by a grieving mother who's husband the architect killed... and the mother's son entraps Barta's character together with the architect because he loves her and doesn't want her to leave.... but in the end when the destruction crew comes he finally confesses to her still being trapped in there and she is saved. By this time Barta has killed the architect, not because he was going to hurt her, but because he wanted her to "sacrifice him" so he could die within his building.
My point is, the movie gave every indication to it being about something supernatural. And the idea of some sort of ritual and captured souls within the building was something I was getting warmed up to. But then taking the movie into another direction - a psychotic boy who's in love - left me disappointed as well as frustrated.
As with every rule, there are exceptions. For example From Dusk 'till Dawn. That movie does the derailing in a brilliant way. It takes you on in a new direction half way through but rewards you with a totally twisted, fun and original plot.
I will continue to ponder such rules and will bring them up when I have good examples.