Any scene in a movie where someone is crawling out of an elevator, and you know the cable is going to snap. Or the elevator is going to suddenly go up, or down with the poor bloke still inside., The scenes of this happening in Resisdent Evil and Speed involving this little thing still gives me the willies.
Scenes where people are crapping on toilet, and the sounds of them at work on the task are never that pleasant for me to watch or overhear. In the movies or in real life.
The scene in ALIENS and AVP where the Queen rips off it's egg sack always make me squirm to a small extent. I don't know why,but it just does.