One Year of Bootstrapping a SaaS Startup
indiehackers.com
indiehackers.com
The ability to pick your projects is a dangerous red herring. You want to focus on what the customer needs rather than what you want to do. The "I made this" attitude works against you. What makes your projects successful is listening to customers and solving their real problems and executing with optimal velocity. Not being a super programmer doing cool things.
The real motivations I see that is unique to these side projects is more participation in the upside. Even side income is dangerous as it distracts you from your career.
On the other hand, if success is not a motivation (and why does it have to be?) than ignore everything I said.