This question requires honesty and a lot of thought – I'm still puzzling this one out myself. It's easier to do with a pencil and paper, and can take between five minutes and hours.
Take some things you do, or want to do. For each:
- Why do you want to do it?
- In doing it, what are you trying to avoid?
- If you could magically achieve all of the things you've currently got written down without doing it, is there any reason you'd still want to do it?
- Repeat the previous step until therre's nothing left.
Repeat this process on each of those goals until you've got ones that seem fundamental enough. You'll know this when you've only got a handful, instead of hundreds or thousands.
I don't expect too many responses to this question (it's both difficult and deeply personal), but it'd be interesting to see the similarities and differences in people's responses.