What's fast, messy, and goes in circles? Serena's love life. First, Dan easily manipulates her into dumping Colin since he hadn't yet quit his job for her, so she immediately puts out her feelers, inviting Dan to the ballet. But then Colin does quit his job at Columbia (seriously, for a 20-year-old girl he's not even officially dating yet?), and there's a supremely awkward moment when Blair delivers Colin to S as Dan watches, disappointed. Also, must Nate really needle Dan about being Serena's backup?
It doesn't matter anyway; Serena and Colin are broken up again by the end of the episode, and because S is physically incapable of being alone, she calls Dan. Nate picks up her desperation signals too, and asks for another chance — right as Dan arrives. And like that, S is back in a love triangle with Dan and Nate. Wake me when it's over.