A combination of factors:<p>1. I hate having a "boss" in the traditional sense. I'm a very independent, unruly and sometimes obstinate person, and I chafe at being told what to do. I like being able to "call my own shots" to a greater degree. I also like not having somebody micromanaging my every decision.<p>2. I'm a <i>horrible</i> employee. I'm insubordinate, arrogant, brash, outspoken and highly opinionated. Nobody in their right mind would hire me.<p>3. I like building things... in the case of a startup, I get to build both "product things" and the company itself, so it's like killing two birds with one stone.<p>4. I like challenges.<p>5. I like the idea of having a big exit and gaining a measure of independence by at least being independently wealthy. In other words, having "FU money".<p>6. I want to build the kind of company that I'd want to work for, if I wanted a job in the first place. Or, at least, the kind of company I want to see exist.<p>7. I think we can do some things to make the world a better place. I reject the notion that capitalists are <i>just</i> selfish robber-baron types who just want to accumulate as much wealth as possible at any cost, with no concern for the welfare of others. I like the idea of building a company that will be socially conscious and actively do things to try and make things better outside of our doors.<p>8. I have some ideas I'm really passionate about exploring, that I think may have some commercial value. At the very least, building a startup in this space gives me a platform to research stuff I'm interested in. Worst case, if we fail as a startup, I'll have learned some neat stuff.