I would argue that we are all a lot more alike than most people think. True, there are superficial differences such as where you grew up, what kind of things you spend your time doing, but ultimately we are all part of the same species and share an enormous amount in common. I'm not saying that people have other goals and little projects they like to work on, but ultimately our purpose is to reproduce. If it wasn't we probably wouldn't be here.
I agree that we all want to leave the world a better place, but think about it for a second. We are not going to benefit from a better world in the future. We are not going to benefit if we save the planet and 500 years from now human beings are still around. Who will benefit from this? Our children and their children.