I'll take a shot: Life is a disease of chaos that spreading itself across the universe that long forgot about it. In order to survive it must consume itself, but keeps spreading slightly faster and has only recently started to shape its own future.
We as a species? We do it because it feels good for the most part. Nature was cruel and we figured out how to keep the pleasure center of our brain happy, and are trying to do that as efficiently as possible. Evolution is cruel and humans are no exception. When primates are threatened they go straight for the throat and balls to remove all challengers. We as a species can get more together; but greed has tipped the balance. Hard times are here and it will likely take drastic change to correct the scales.
We as a collective individual? As our perspectives and priorities change, there will never be a single answer for an individual at any point in their life, so it's hard to provide insight to anyone reading. The first task is to get to know yourself, what are you good at, what do you suck at, what's the most attractive part of your body, what's your best hairstyle, we are all unique and unless you can honestly answer this, you still have work to do. If you had unlimited cash, what would you do? Keep in mind quit my job is not an answer! Aside from getting bored in a few weeks, the actual point of this exercise is to identify what your priorities are. Would you run an organization to do something? What's your passion project? It might be to spend it with your family and that's a great answer for a happy life. Bill Gates went to Africa to help people, Elon Musk bought Twitter so people would talk about him. At the end of the day, your reason for doing it and mine will be different, but you need to find what you can do that will bring you efficient happiness. If it helps; I like chasing a lot of different things and finding the best it has to offer, I also love my dogs. Best of luck in your search.