Well, seeing how we've been having a lot of recommendation threads recently in these forums, I thought it was time for a discussion thread or two once again.
So here's the topic: What are some of the greatest emotional moments in manga or anime that you've seen - and more importantly, why did they stir such emotions in you?
Going into greater depth is preferred. Spoiler warnings are probably a good idea, but otherwise feel free to wax eloquent about how a particular scene has inspired you/made you cry/changed your life/given you screaming nightmares/dissolved you into a puddle of warm goo, etc. You might also want to discuss the techniques used by the mangaka or anime director to evoke such dramatic power from the scene.