Seriously, what's John McCain's problem?

I just don't get this at all:

[Obama] walked over to where McCain was chatting with Republican Sen. Mel Martinez of Florida and Independent Sen. Joseph I. Lieberman of Connecticut. And he stretched out his arm and offered his hand to McCain. McCain shook it, but with a "go away" look that no one could miss. He tried his best not to even look at Obama.

Finally, with a tight smile, McCain managed a greeting: "Good to see you."

Obama got the message. He shook hands with Martinez and Lieberman -- both of whom greeted him more warmly -- and quickly beat a retreat back to the Democratic side.

This was yesterday on the Senate floor. Pretty incredible when paired with McCain's inability to look at Obama during the debate. The only thing worse than a sore loser, is a person who's sore even before they lose. I have no idea what's going on in McCain's head. But one has to wonder what sort of unhappiness, what manner of poison brings you to this. Does he even really wants to win? Or is he simply animated by the sense that he was robbed in 2000? I hope there is a reporter working on a piece about the internals of this campaign. Again, I have no idea what's rattling around in my man's head, but boy, he really seems in pain.