The Starland Vocal Band were on to something. In their 1976 hit ‘Afternoon Delight’ they sang, in gruesomely twee harmony: ‘Gonna grab some afternoon delight/ My motto’s always been when it’s right it’s right/ Why wait until the middle of a cold, dark night?’ Granted, they were singing about rumpy-pumpy, not theatre-going, but for many of us the same principle applies.