Business Green: So how was it for you? Disappointing, frustrating, more than a little upsetting? Join the club. In keeping with the somewhat sordid seasonal traditions of the office Christmas Party, world leaders will find themselves waking up this week feeling secretly ashamed at their behaviour, while trying to convince themselves that no one noticed and everything will turn out all right in the end. The sad truth is that almost all the epithets thrown at the Copenhagen Summit in the past 48 …