Recently, our Tech team and myself got together to make a list of all of the things we forgot about in the last year, when working on various projects. There are 20 items so far, and it’s still growing.
When your product is complex and you make “one small improvement”, the butterfly effect is amplified enormously. The more primary use cases you have, the more edge cases you have. The more users you have, the more rare occurrences will, in fact, occur.