I wrote about beauty last year and linked to a great article in the Washington Post on how our perception of art and beauty is shaped by our readiness for it. In the article, a world class violinist plays in a train station and is largely ignored.
The Gestalt school of psychology tells us that we see things as a whole. We try to make sense of a photo (or a painting or a website) not by breaking it down into individual parts but by mentally grouping them all together into a whole - hence the expression "the whole is more than the sum of its parts."
Studies regarding perception have been done for years such as the duckrabbit experiment. The conclusion drawn from these experiments is that we do not merely see a set of lines, we see them as a duck (or as a rabbit). Experiments like this show us that, even when people are seeing the same thing, they can see things very differently.
I used to repeatedly go ten rounds with a co-worker over an issue related to our website. We were both looking at the same metrics but drawing completely opposite conclusions. I think she was seeing a rabbit and I was seeing a duck.
The same can be true when designing (or redesigning) a website. The design and organization and usefulness of the site should not be just about your organization and your perception. If it's going to be successful, it needs to reflect and incorporate the perspective of your website's users.
Our job is to see the duck and the rabbit.