File this under "take you lessons from all parts of life".
Recently there has been a lot of buzz about a picture of "Bigfoot" on Mars taken by the Spirit rover. As an amateur astronomer and a skeptic this has been humorous and disturbing to watch. You have to wonder how people could actually believe that this might be a life form. We are talking about a planet with very little atmosphere and no magnetic field to protect it from cosmic radiation.
If you take a look at Emily Lakdawalla's blog post you will see what people aren't mentioning about this image. The rock is actually two inches tall and only a few yards from the rover.
So what can we learn from this that we can apply to software development? Look at the whole picture. The perception the individuals have within a project are colored by how much they actually see. Someone who does data entry can give you really good information about how certain screens should work, but they may not have a good corporate picture of where everything fits together. We need to spend time looking at the panoramic as well as the macro.
Another thing we can learn is to understand that people see what they want to see and have their own agendas. Some people may see Bigfoot because it supports some of their other beliefs like the Loch Ness Monster. A manager may want a feature implemented because it will keep their employees busy, but it may not actually be in the best interest of the company as a whole.
So don't take things on face value. Ask as many questions as you can without grinding the project to a halt. Even then, some questions may be important enough to stop the project. If it is in the best interest of the company you have to ask the hard questions.