This week’s Imagine… Jeff Koons: Diary of a Seducer (BBC1, Tuesday) began with Koons telling a slightly puzzled-looking Alan Yentob that what spinach was to Popeye, so art is to the rest of us: a way of achieving transcendence and appreciating ‘the vastness of life’. As it turned out, though, not all the claims made in the programme were quite so straightforward.