I guess as a programmer I'm too logical. You tell me X hours, that's all I'm going to spend. For one of my past interviews I was given a task to make a multiplayer battleship game using whatever I wanted, and was told to spend 2 hours total and they didn't expect me to finish.
I got some rudimentary client/server communication going and that was it. No game logic at all.
Didn't get the job: "However, we would have liked to have seen you get further on the project in the same amount of time."