In 1997 Gary Kasparov was world chess champion and believed to be the greatest player ever. In an historic tournament he was pitted against the best artificial intelligence had to offer, IBM's Deep Blue.
Kasparov wiped the floor with Deep Blue in the first game and a similar result was on in the second. Given the many moves possible by both players, even grandmasters are only able to think 4 or 5 moves ahead. Midway through the second game Deep Blue made a move that threw Gary. This move seemed like a backward step. It didn't progress it's attack and it hardly bolstered it's defence. Yet this super computer made such an ordinary move. This panicked Gary. Could it be that Deep Blue's processor could assess far more moves ahead than he could? Could it see a future possible situation where this would be the best move?
If a computer could think this far ahead how could he ever beat it? The first game must have been a learning process and now it had figured out his style of play. Could this be the end for human intellect? These are the thoughts that worried Kasparov and eventually he forfeited the second game.
This dread affected him so much that he lost one more game and drew the others. He lost the series 2-1 and the world's best human was beaten for the first time by the world's best computer.
Years later the truth came. Tournament rules require a move to be made in a set amount of time. In 1997 even super computers were only so good. It couldn't calculate every possible combination of move and response in the time limit. So it's programming made it perform a safe default move so it didn't forfeit the game. In essence Gary's mind was beaten by Gary's mind. Or in simpler words, he over thought it.
A good reminder to always play your own game and not to over think things so far into the future. We never really know what's going on in someone else's head. We can never be 100% sure of what motivates peoples actions, so let's not over engineer things.