I just like building things. Cool things are more fun to build, but not everything needs to be in that category. I'm in software because it's significantly cheaper than other ways to build things. I love working on open source software because you can build bigger and better things with a team, it builds good will and unless it's core to a business, there's no reason not to. I'm shooting for a certain dollar amount that would let me work on what I want when I want, not just for the things that come with the money. But on the route there I refuse to give up the enjoyment of building things with a preference to cool things.
On the other hand, I only hear about the feature as a product or network effect startups here on HN. Around town, folks I interact with and companies I all work with have real products and at least a real revenue source.
It's like going to comic-con and deciding the rest of the world dresses like that.
I also love building things, but, to use an analogy, I also love playing music. I practised for years and years, until I could pick up whatever music I wanted to play, and then I wanted more - some kind of validation - so I wanted to play to other people.
It is a bit the same with me and programming/developing. Revenue is my new metric for how well I am doing. It makes it harder - yes I can come up with a solution, but can I do it in a short time, suppressing my perfectionism (come on - we all have it), and in a responsive enough manner to get people to pay for my work? It is just taking it to the next level.