The moment that inspired this question:
A long time ago I was playing an MMO called Voyage of the Century Online. A major part of the game was sailing around on a galleon ship and having naval battles in the 1600s.
The game basically allowed you to sail around all of the oceans of the 1600s world and explore. The game was populated with a lot of NPC ships that you could raid and pick up its cargo for loot.
One time, I was sailing around the western coast of Africa and I came across some slavers. This was shocking to me at the time, and I was like “oh, I’m gonna fuck these racist slavers up!”
I proceed to engage the slave ship in battle and win. As I approach the wreckage, I’m bummed out because there wasn’t any loot. Like every ship up until this point had at least some spare cannon balls or treasure, but this one had nothing.
… then it hit me. A slave ship’s cargo would be… people. I sunk this ship and the reason there wasn’t any loot was because I killed the cargo. I felt so bad.
I just sat there for a little while and felt guilty, but I always appreciated that the developers included that detail so I could be humbled in my own self-righteousness. Not all issues can be solved with force.
Brothers: A tale of two sons. Not a unique experience, as it almost seems like the whole point of the game is this one moment. So, spoilers… Its control scheme is each analogue stick independently controls your two characters, two brothers. And it's a fun puzzle game where you have to resolve moving two characters at once in this way, moving, balancing, timing. It's all fun and games until a tragedy, the older brother dies. He was one of your control sticks, now for the rest of the game half your controller is dead also. And you walk back out of the cave past all the puzzles you did with your brother, which are made for two people. You're useless, and the feeling of loss is staggering.
-Spoiler- The strongest moment in the game uses the control scheme as story and character development. Only the older brother can swim. After he's died, you hit a dead end with deep water in the way. You use the older brother's control stick to swim through it, relying on what he left you with.