Waterboarding

Vivid accounts of waterboarding (like this one that's now been linked by Matt, Ezra, Andrew, and probably others) are an extremely potent way of taking this word--"waterboarding"--and hitching it to images that accurately convey how deeply cruel and inhumane the tactic really is. But part of the reason there's a dissociation to begin with is that, as I've written before, waterboarding is often described half-correctly as a technique that "simulates the sensation of drowning". To wit, though waterboarding does create the sensation of drowning, it's not by simulating anything. Instead, if done correctly, it all-but-drowns its victim. If it's done with too much force, then the victim dies... of drowning. So, if you're being waterboarded, you can't just ignore the discomfort and put your mind over the matter of what's happening to you, secure in the knowledge that it's all just a harmless simulation. Because, well, you're actually dying.

Think of the distinction between simulated freefall (putting somebody on a roller coaster, say, or a bungee jump) and dropping them off of a cliff without letting them know about the safety net at the bottom, and you'll understand the difference much better.