Quote:
Originally Posted by
JammieDodger 
His intention for turning it down was to not be recognised for something he considers as trivial.
He does not consider the conjecture, or its proof, as trivial. He just considers he is only one of the many people who made the proof possible and does not deserve it more than them.
In a nutshell, this is him saying he does not agree with the way the mathematical community works, the way it awards praise, etc.