I love the story of the two architects who were walking in the woods when they came across a disgruntled mother bear. The one architect asks, "do you think we can outrun her?" The other one replied, "I don't have to, I just have to outrun you." Ah, yes - understanding the problem in context.
At the end of every episode of the Flintstones, Fred would attempt to put the cat out. The cat (apparently smarter than Fred) would immediately jump through the open window beside the door. This explains why Fred never became an architect.
Missing the obvious is a human attribute for which we all fall victim from time to time. Psychologist Dr. Richard Wiseman conducted a study whereby participants were asked to count the number of photos in a newspaper. Most of the people were able to complete the task in a few minutes, some took longer because they rechecked their counts. They needn't have bothered because page two of the newspaper contained a headline with a typeface 1 1/2 inches high which read, "Stop counting, there are 43 pictures in the paper."
I love this picture and use it frequently to make a couple of points. First, take a close look and make sure you can spot the gate arm that is supposed to stop cars from entering and exiting the parking lot. Now note that as a car enters the lot (from the top of the picture moving downward), there is no place to insert a ticket or otherwise identify the car or driver. Therefore, the gate must just open automatically. For everybody. Well, maybe this is a heavily trafficked area and the gate serves as flow control. Hmmm, the serenity of the narrow streets and grassy lawns would seem to suggest that traffic congestion is not an issue.
Of course, there is the obvious indication that the gate merely impedes traffic for no apparent benefit, as evidenced by the turf marks clearly seen in the light snow. Good designs just work. This one doesn't. No one planned for this gate to be useless, in fact, there may even be a good reason for it. But, this particular design fails. If you are interested in application security, this would be a good example of how a bad design only considers the users that want to follow the rules.
If you are a user interface designer, this is a good example of how an 'intuitive' solution can be misused. Oh, the lessons that can be learned from this one photo are nearly endless. How about this; when a important task is at hand (in this case, maybe... getting home?), people tend to use the path of least resistance. Think about the solution you are designing right now; is the use of the solution (in the eyes and hands of the user), the path of least resistance?