The client mentioned to me, "Hey that's funny, was that done on purpose?" I looked with a blank stare and said something intelligent like, "Huh?" She said, "Your wellness room is right next to a conference room titled, 'Fever.' That's kinda funny!"
It took me a second to get what she meant, but sure enough I looked and saw a sign labeled "Wellness Room" (where ill employees can rest) about ten feet away from a sign labeled "Fever" (named for our local women's professional basketball team, the Indiana Fever, which by the way, is a great WNBA team).
Even though I was involved in designing the interior of the office space and the signs themselves, I never noticed it. After all. Who would?
It is a rather silly example, but it is amazing how many things your customers may notice that you would never even consider. It's one more reason to really know your customers - to understand your business through their eyes so you can see the things that would never even cross your mind.