Gather 'round children, and I'll tell you a tale. The tale of the subway station called Fulton Street, where people go in, but no one ever goes out. Particularly if you have entered through the opening on Broadway, and you are seeking to take the M train downtown into Brooklyn.
Behold! When you are upstairs, there is no sign for the Brooklyn-bound M train; only directions for getting to the M that goes in the opposite direction! But get to the train you must, so you descend. Only to find that the same directions exist below as exist above, directing you to take the same staircase over and over again until you lose your mind.
Finally when you buy a churro, wipe the cinnamon and sugar from your mouth three times, and say, "You have no power over me!" the tiled walls move, and the correct passage way is revealed to you.
I have spent 20 minutes in this station on two separate occasions searching for the same track.