Software development starts with user need something. And software or app supposedly get developed, so user can use that do things more efficiently. But most of time, we failed to understand user. Let me give you example.

So long long back, when I was studying programming, our seniors developed billing software for one local shop. They may have more that one store, I don't know. Requirements was given by owner. One of faculty was friend & he was aware with requirements. Application was developed using VB6 & MS-SQL7. They took really great efforts. There was 1 prototype demo happens with managers. Software was deployed. But next morning, same faculty get call. Application was not working properly. After seniors & faculty visited to see how operators using software. They found that, user enters data in first field & to go to next field they press ENTER key & not TAB key. All those operators using old software, which was developed in such way that ENTER key was used for jumping to next field, instead of tab key. That application updated to use ENTER key like the way user wants.

Second example. We have team of mix between experience, fresh coders, some of want to jump from frond-end to back-end & others back-end to front-end. And couple of times people asks to suggest books. And to reply that others with subject matter expertise suggest books, video tutorials, online courses, etc. Now if you go by request, it was for book, but we know those people, we know they want material for learning & not just books.

Similarly in first example, if someone just went to shop, sit there & observe how users were using existing software, it could gave more inputs. Getting written & verbal requirements & understanding those is important. But it also important to understand user behavior, existing experience & context. When user ask for certain feature/functionality, its really really & really important to understand why user want that & how they use that functionality. Nowadays more famous word for this "Empathy"