Have fallen back on this thought for ages. Was especially important to remember when my kids were young: When they were being stinkers...this too shall pass; and when they were being practically perfect...this too shall pass. One of the great circles of life.
Saving people is a really hard task - it won't always work. But what you can do is love them, make them feel special and let them know there's someone who cares about them and that their life is worth living.