[llomlup]

First, while it's a noble goal, to save the world requires a position of power. So, your goal is to obtain some power. The problem with power is that it corrupts, and it may happen that once you yield significant amount of power, you may not want to use it as you may have originally intended to, because it might be too risky and as a result, you could lose it.

Second - thus, your goal now is to maintain the achieved level of power and look for ways to enlarge it.

Keep in mind that many people don't really care about the good in the world, let alone saving it. Their perspective is a personal one, I'd say even a selfish one.