I recently enigmatically tweeted As a rule, rules are wrong.
I was partly thinking of Imagination vs. Art in Horror Film, Comics, and Literature by Curt Purcell. He is posting on the conventional wisdom that what one imagines is more frightening than what one is shown.
Clive Barker and Dread screenwriter/director Anthony DiBlasi repeat it in their discussion on the Dread DVD.
I'm not going to step on what Curt has to say, which is all quite interesting and much more detailed and considered than what I have to say.
I know what people are getting at. There are tons of examples, many likely better, however what always strikes me an explicit use of this is the ear-cutting scene in Reservoir Dogs. At the key moment, the camera turns away and looks at the wall. It seems to me, it's self-consciously mimicking the human reaction to turn away from such a horrible violent event.
And it works.
So, I'm certainly not saying that the "rule" is wrong, out of hand, but it is pretty silly as a rule if you think about it. I mean, if my imagination is so much scarier than anything that a movie can show me, why would I need to bother watching a movie at all? Why don't we all just go to a dark theater, listen to some creepy music, take a nap and have nightmares together?
No, really. I mean, all movies are making choices between what to show to evoke the fears that the creators are imagining and wanting the audience to experience. The choices are difficult and require balancing what one shows and what imagines. It's not an easy balance, that's why so many fail.
If there was a rule, it would be easy. I'm not sure that would be preferable.