Local rewards add up
Animals select their short-term behaviors under the guidance of their reward mechanisms. This leads to local maxima, which are not necessarily global maxima. You should set up your environment so the most locally-rewarding actions move you in the direction of a globally optimal future.
How do you think I convince myself to post regularly on this website? It only takes about ten minutes to write and upload a short post, it’s fun to put a thought into words, and I know somebody is going to read it and benefit from it. If I’m bored or in between tasks, writing something on here is the most immediately gratifying thing I can do. That’s why it happens automatically—why I don’t have to apply discipline. I’m having fun.
People end up doing whatever they find rewarding, which are not necessarily the things they set out to do.