Undertale had an effect like this for me. [Warning: spoilers] Near the beginning of the game you are forced to fight a character who has been nothing but kind

Undertale had an effect like this for me. [Warning: spoilers] Near the beginning of the game you are forced to fight a character who has been nothing but kind to you. The easiest thing to do was kill this character to progress, but immediately after I felt regret and a strong desire not to have done that. Fortunately I made the decision not to save and so was able to revert my decision by taking the more difficult – at the time, far less certain – path of refusing to fight the character. (Though I still felt bad; and the game doesn't let you forget entirely either.) Another belief-altering moment from the same game came after reflecting on the gameplay as a whole – I had developed an affinity for the main characters in a way I hadn't in any other RPG. I realized that this was due to the characters initially not liking me, and me having chosen to do things which didn't benefit me at all in order to help the characters achieve their goals, which resulted in their friendship. The option was always there to simply kill them and move on. But the act of investing energy doing things solely for the benefit of these characters built a relationship – and I realized that this is ultimately the basis of all human relationships.