One of my favourte lessons was to add sound to our thriller opening. The sound we used was just perfect for our film, it was upbeat, tense, touching, grim and really keeping the audience on their feet. We used one track throughout the clip which had razors, screaming, hammers all in the background combining with the killer and his actions.
The soundtrack was made of different dangerous items to create the feeling of power, of a complete psycho, someone out of their heads, not normal demonstrating to the audience that the sound has a major saying in the clip.
Personally, i think the sound is part of the story telling, depending on how u present the sound will depend on how the audience create a stereotypical image of your clip. The opening is only two minutes, so therefore the audience have to be left amazed and feel that connection with the film, we want to leave our audience confused, thinking whats going to happen? who's the killer? why does kill?