Ask HN: How do you come up with project ideas?

My Pretty Diff application basically combined language beautifiers with a custom diff engine. The need came from working with minified code and expanded to a variety of other things experienced at work.

My Share File Systems just started out as an experiment to see if I could navigate the local file system in the browser better than the local OS. Then I wanted to see if I could share access with other computers on the same network and then privately across the network using a new privacy model. Then I need distributed test automation for peer to peer applications to test it, and some other things not present in Node or the OS at the time.

for me they're basically all necessity driven, "track mpg of car" or "need to learn this to do that" kind of things

In my experience, there are way too many ideas and no where near enough time.