Christmas Day lunch is the ideal target for the newest but already most tedious Christmas tradition of them all: the ritual moan about the terrible excess and waste. You know, all that money spent on too much food, of which too much is eaten, too much is thrown away and too much is bad for you. I’ve been as guilty of this as the next party hat refusenik. Yet I wonder whether the Yuletide vices we loathe are just the shadows cast by the festive virtues, and we can totally escape the dark side only by destroying the splendours that block the light.