Idea: Make software for the Olympic sport of bicycle motocross.
Execution: Flawless. Built the app in Elm + Ionic Capacitor. It looks great and works perfectly. There's even a Web version at https://gearbag.bike
Marketing: lol
Result: I have spent five digits of money (paid my friends market wages for their help, particularly with UX and design) and made $6 from Google AdMob and have ~100 installs.
Worth it. Doubling down on the next project this year.