When people can see and track progress, they are more motivated to complete their goals. This relates to the 50th thing every designer needs to know about people and can be found several chapters before this one. Hint, go faster, you're almost there.
Why is it that we do some things for free when they don't involve monetary rewards? Because sometimes we just want to get better at something and master it.
The accomplishment we feel along with the knowledge and mastery is the intrinsic reward we are giving to ourselves.
Wanting to master and control something is the motivation that keeps us doing the things we love. We want to get better and better and learn as much as we can about things that interest us.
In Daniel Pink's book Drive, he says that mastery is like an asymptote in the way that it is something that can never fully be reached, but that doesn't stop us from trying.
