Best software I’ve developed so far is a digital board game implementation.
1. Clear requirements (make the game, by this rule book).
2. Aside from minor UI quirks it’s practically bug-free. All reports of the last 2yrs have been closed (not by me) with: “Nope, *you* read the rules wrong.”
For people who care about, support, or build Free, Libre, and Open Source Software (FLOSS).