Un Chien Andalou is a classic. It pushed boundaries that were completely unheard of in the 1920's movie making industry. But still, it's not one of those things you can easily un-see after you've seen it, especially if you don't have the stomach for horror flicks. I have the stomach, and the eye-cutting scene is just too much for me. Even though it was the eye from a cow, and the cow was dead, it's still too much. I think it's something to do with the mutilation of such a vital, frail organ. In anatomy class, I have no problem discovering the different layers of tissue, but it's a bit grotesque for shock effect on film. Which I guess was the thing Dali was going for - reality was a perceptive event, and surreality is always lurking just under the surface.
Btw - that videotape in "The Ring" gives me the uber wiggins every time. I cannot watch it.
And yeah, I totally have issues with watching Xander get his eye jabbed out. Makes me just hurt for the guy. Makes me need a hug.