My 2 cents. Coding a side project is "fun hard", for a developer, while marketing and selling it is "hard hard". You could consider for your side project, an ap

My 2 cents. Coding a side project is "fun hard", for a developer, while marketing and selling it is "hard hard". You could consider for your side project, an app using the API of a platform such as Heroku, EventBrite, Slack, Shopify, and so on. These platforms could help you make the marketing (a bit) easier, by exposing you to users in their app store/directory/marketplace. As a result, that's one of my criteria for side project. As far as finding an interesting problem to solve. PG explains in a follow-up essay, I think, that most people get used to suboptimal situations. We, as human, are very good as rationalizing painful situations, processes, etc, as normal and good. You need to take a step back when something is long, boring, repetitive or annoying. Is it really necessary? Couldn't it be automated? Question your assumptions :-)