Saving a person’s life feels great, and it would probably feel just about as good to save one life as it would feel to save the world. It surely wouldn’t be many billion times more of a high to save the world, because your hardware can’t express a feeling a billion times bigger than the feeling of saving a person’s life. But even though the altruistic high from saving someone’s life would be shockingly similar to the altruistic high from saving the world, always remember that behind those similar feelings there is a whole world of difference.

Nate Soares, On caring, Effective Altruism Forum, October 6, 2014