Chuck tells Dan that they're from different worlds, and that Dan, by virtue of his middle-class stature, can't afford (in so many ways) to get suspended or expelled. Chuck, by contrast, can simply have his dad buy his way out of trouble.
Despite the efforts of Serena's evil grandmother, Dan sticks it out and wins the affections of Serena at the ball. It helped that Lily stood up for him - and herself - by swallowing her pride and admitting she'd been unfair.
We make our own fortunes, and call them fate. And what better excuse to choose a path than to insist it's our destiny? But at the end of the day, we all have to live with our choices ... no matter who's looking over our shoulder.