Are there any movies that you regret having someone else watch?

For me, I had a friend watch "The Grudge" based on a memory of it being pretty scary. I failed to remember that it was the first real horror movie I watched.

I also had my wife watch "Trainspotting", which I think is a good movie, but didn't realize we had different tastes than I.

We have seen "Green Inferno" (gore porn with no real story) and "First Blood" (Amazing but immensely depressing) together from others' recommendations to me without me pre-screening them for her.

Are there any movies you showed another, expecting them to like it but were proved wrong?