The scene from the movie Michael Clayton where the two hitmen paralyze the victim but leave him conscious while they inject him with an overdose.
It was just so creepy.

Also, a short documentary I watched about how animals are treated in China. They apparently skin them alive because it comes off easier that way.
There's this one shot of a poor little thing with all the skin peeled off its face but its eyelashes somehow still attached, just lying there panting and blinking and looking pitiful on a pile of others just like it.

The Red Wedding was pretty shocking. Especially if you're too stupid to figure out why it's unusual for someone to be wearing chainmail at a wedding feast.