I once spent 6+ month working on a feature that was to be one of the flagship features of our next major release. We'd talked to several major customers about i

I once spent 6+ month working on a feature that was to be one of the flagship features of our next major release. We'd talked to several major customers about it and gotten lots of positive feedback. Once released, virtually no one used it and no one cared. On the flip side the by far most impactful feature I've ever added to any software in any point in my career came a couple of years later when working at the same company. It was inspired by an offhand comment by someone in a meeting, and it wasn't anything anyone had ever asked for or even really solving a problem customers claimed to be having. I'd 'coded' the feature on a piece of paper by the end of the meeting and implemented it 2 days later, mostly just to see if it would work. I quietly added it in a minor point release with only a 1 line mention in the update doc. That feature went on to become an everyday part of most of our customers workflow, and transform how they used and interacted with our app. Nobody, least of all me, had any idea how useful our customers would find that feature.