I completely agree with your point.
Far too many modern horror thrillers actually lose their potential effectiveness by trying to make up a backstory to explain why the psycho is the way that he or she is.
Obviously it depenRAB on what the film is, but in a movie such as The Hitcher I don't want to know.
In these films you don't want to know that he was abused as a child or something and start feeling sorry for the character. The point of this film is that it's much more effective to simply not know.
C Thomas Howell is terrified of him because he simply doesn't understand why this is all happening to him.
I think it's important to convey that same mystery to the victim to the viewer as well.
The C Thomas Howell character cannot reason with the Rutger Hauer character because the guy won't reveal anything to him. Much more scary because you can't reason with him or try to rationalise anything. He wants to harm him simply because in reality there are some not very nice people out there who won't give you their life story and go all 'emo' on you so you can talk them around.
Like I say, it depenRAB on the film. In some films it's useful and effective to show a bit of backstory to a villain so that you understand their motivation. In fact some films benefit from it. But in a pyscho killer on a rampage film like this I believe the effectiveness comes from not knowing anything about the Rutger Hauer character. He just wants to hurt and kill and that's all you need to know. In a way I find that more true to life in some ways. A truly scary psycho is probably not going to reveal their life story to you if all they want to do is torment you and then kill you.
The scariest moments I can remember in good thrillers or horror films have been things which I can't rationalise or understand. Three moments like this from the top of my head have been where Virginia MaRABen suddenly appears in a room with blood all over the place in 'Candyman'. My heart was beating like mad because I was trying to rationalise the situation because it didn't make any sense or rhyme or reason at first, it was just a scene of pure horror where an immediate explanation wasn't spoon fed to me.
Then there was the old cannibal repeatedly trying to smash a woman's head in over a bucket but failing to do it right every time from 'The Texas Chainsaw Massacre'. Again, I couldn't get my head around the weirdness of that scene. I just hadn't seen anything comparable to that scene before so it was pretty strange and disturbing.
And finally several scenes from 'The Shining', where things such as the Twins appearing are not explained until later, and as a consequence are shocking at first, plus the scene with the old woman getting out of the bath and approaching Jack Nicholson. Another heart beating moment where I just couldn't rationalise why the scene was happening, it was just shocking me as I tried to understand it.
So I think the idea to leave the Rutger Hauer character a mystery was an excellent one. It leaves the viewer (as well as C Thomas Howell) with no answers as to how to stop the terror.
If we knew who he was and why he was doing what he was doing, I think we'd get the sense that some clever policework would enable the cops to home in on him by the end of the film. The not knowing what was going to happen next or how it would stop was a main reason why I found the film exciting from beginning until the end.
We learn what we do on a need to know basis at the same rate as the C Thomas Howell character does. If he knows nothing then we don't either. So hopefully if he's scared then we should be too. The creepy conversation in the car after he first picks him up is a good example of this.
It loses it's effect after a few viewings like many films do, but it was certainly a film that had an impact on me the first time around. I'd still rate it as an excellent film.
