Charles Lamb was the first Scrooge of Valentine's Day. "The weary and all forspent twopenny postman sinks beneath a load of delicate embarrassments," he wrote in 1819. "In these little visual interpretations, the bestuck and bleeding heart is twisted and tortured into more allegories and affectations than an opera hat."

Lamb's complaint about the annual cacophony of valentine kitsch is mirrored in the contemporary dismissal of this day as a Hallmark card holiday an excuse for the market to sell infinite varieties of tat.

Yet commercialism is not solely to blame. Valentine's Day is a unique public ritual, one that celebrates private passion. In other one-day festivals, like Halloween or bonfire night, the rituals are relatively fixed and have little private meaning.