Is it really a good quality that someone might be willing to sacrifice oneself for a stranger? Let's imagine a theoretical scenario in which a small child is about to be hit by a train. It's just you and the child; nobody else is around. You can either let the child be hit by the train with a 100% chance of death, or you can sacrifice yourself with a 100% chance of death, but a 100% chance that the child will survive.
Should you sacrifice yourself to save the child? I'm not so certain. It's safe to assume that if you're reading this, you're older than the child I'm picturing, so the child would probably live longer than you, and therefore all things considered, he or she would contribute more to society. We have no idea whether this child will grow up to be a good or evil person, of course. But, what we do know is that if you're the type who would sacrifice your own life for a random kid, you're probably a pretty good person. So, society trades a person who's almost certainly good (assuming that fewer than 50% of the world would make that sacrifice, which may not be true) for a person who has a 50% chance of being better than average and a 50% chance of being more evil than average. Plus, if you assume that for the first quarter of your life you're pretty much just a drain on society, it makes that older person even more attractive, especially if they've just finished that first quarter of theirs.
It looks to me like society's probably better off if that really nice person just lets the kid get hit by a train.
My, that's morbid.
So, what's the point of this post? If you ever go with me to play near some "abandoned" train tracks, watch your step.
(I assure you that I have no secret motive for posting on the topic of sacrificing one's own life on Easter Sunday. Just something that came to mind.)