Working in the world of websites, I sometimes forget how important good UX design is in the real world. A professor at NYU analyzed the London Tube system and discovered that up to 30% of passengers take longer-than-necessary routes because the Tube map misrepresents the distance between stations. Despite this major flaw, the map design, which dates back to 1931, has been copied by cities around the world. (I can attest to this being the case in several South American countries, at least.)
Here, you can compare the map to the actual layout:
Pretty crazy, huh? Research found that passengers tend to trust the map more than their intuition or experience, which shows what powerful impact maps have on our perception and how, in the web world and real world alike, you get what you design for. Check out the full article in the Daily Mail.