I have a kind of FOMO when it comes to knowledge. If I run across a topic that could conceivably be useful to me or my family in some way, I HAVE to gain at least an entry-level understanding of it. And since the best way to learn is by doing, I basically start projects all the time. The feeling of going from zero knowledge in a certain area to much more than the average Joe in a short amount of time is exhilarating. But of course the learning curve flattens out and linear gains require exponential work. That's when I know my curiosity is satisfied and I have enough background now that I can always come back later for a deeper dive if I want or need to.
This is not to say I never finish ANY projects. But I need to be very selective about those because life is busy, I don't always take pleasure in the journey, and they always end up taking 10x more time than my most conservative estimates.