I spent most of my programming career working for small companies and doing almost everything myself (including collecting requirements, design etc.) but the last few years I spent with an enormous tech company working on apps with teams of professional designers and UI/UX experts (I've avoided the scare quotes around these terms, with difficulty). The designers always designed on paper, and violently rejected any suggestion that their designs be put in front of focus groups of actual users and modified according to feedback. "Users have no idea what they want" was an actual, frequent quote from them. As a user who does know what he wants and rarely gets it from modern mobile apps, I found this attitude a bit surprising. Not surprisingly, our apps usually averaged barely above one star (thanks to corporate instructions to employees to vote our apps up), with many comments along the lines of "only voted one star because you can't vote zero stars".