Odds are pretty simple to understand -- they represent the value that will get people to bet on unlikely shots. For example, suppose you've got an ultimate cyborg guy with skin of steel and a pair of .45s he can actually legitimately dual-wield without dislocating his shoulders, and it's not some Hollywood crap. And his opponent's a naked teenager. The only way anyone would bet on the teen is if they win a hell of a lot more than they bet, so it feels like the long shot could really pay off for them.

[Zetta is thoroughly Zetta, but he knows some things. His massive stupidity is a reflection on Wisdom, not Intelligence, after all.]