The 20 Most Disturbing Movies of All Time

If a movie is tagged as horror or weird it's a surefire way to make me interested in it. The more horrific or weirder the better.
I'm excited about the prospect of weirdness in films because it usually means I'm in for something different, something that might challenge me and offer an interesting viewing experience.
I had to change the name of this list because the original contains an expression not fit for publication here in List Challenges. And there are 21 films on this list 'cause the Nymphomaniac was listed as one movie in the original list.
Have you seen these movies from the Taste of Cinema's list?