While elated to have snatched victory in the Manchester derby, Sir Alex Ferguson was left with mixed emotions after missing out on the chance to rout the Reds' near neighbours.
It would seem that the brain sees these images as puzzles, and the harder it is to decipher the meaning, the more rewarding is the moment of recognition.
The other thing is that in some countries, the way that biofuel crops are grown and harvested still produces a great deal of pollution—really damaging to the atmosphere.
Some scientists have argued a subset of these high-achievers can be classified as "positive perfectionists, " those who reap the benefits of perfectionism without falling victim to its ills.