He knows that this winter -- when he's 36, turning 37 next May -- he has a better chance of scoring the four-year, $100M deal he has told teammates he can get than he will after the 2010 season, when he'll be 38 turning 39. He doesn't want to have to sweat for two years at a measly $20M, and everyone knows that he couldn't care less how he gets that $100M, even if it means sitting out and leaving "family" fighting it out without him.
That's it in a nutshell.
Manny wants stacks of cash. This is his way of going about it. It's not exactly what one would describe as 'charming' behavior, is it?