What do you still want to learn in this life?
What knowledge are you still missing? What do you want to learn before you die?
Wouldn't it be strange to walk through life without knowledge of X...
Last year I decided that I absolutely need to learn more about world history. It would feel really strange to go through life without knowing what has happened before I got here. And my history knowledge is pretty bad, so there is a real reason for me to improve it. I'm starting from the beginning, last 10.000 years -> present.
It would be interesting to hear what you think.