What makes you more curious about one technology over another?
Which considerations go into crafting something by yourself?
How do you evaluate how useful something you could create would be to others?
I do put in effort to make things useful to other people, and take their ideas to heart to widen the userbase, but ultimately it must be useful to me as well.
I judge its usefulness by the volume of support requests coming in ;-)
In fact, contract work is a great avenue to pursue your dreams. By choosing your work, you can learn valuable skills for your own project. Being exposed to different corporate departments and income streams can spark your own ideas.
If you get in the habit of devoting time to personal projects, you will see where your values lie and pursue that. Not everyone can live the startup lifestyle.