Most of my experience comes from actually working closely with people to provide solutions for the in-house webapp I maintain for work. Many a time have I implemented what I thought was an definite enhancement only to find people weren't using it. After sitting down with people to find out exactly why, I would invariably learn a new facet of the problem that changed my understanding, and made the solution I implemented at best a trade of one problem for another problem of roughly equal or worse annoyance.

Rinse and repeat through a few different business areas in my career, and you can't help but learn a little humility and come to respect the power of truly understanding the problem space before embarking on a project of any magnitude. A powerful lesson, but unfortunately easy to forget.

That said, one of the replies to my comment (that subsequently deleted it) was a HN regular that said "Kaizen principles tell us that there are many optimisations that are known to the people doing the job, but not to the people who have the power to implement them." I wasn't familiar with the term, but I am familiar with what it refers to, and my bet is you'll find good information branches along that path.