I have been given a gorgeous, slightly warm but not at all damp, men’s shirt by Prada — jet black. But taking the shirt off another person’s back has an ancient, damning implication, and there is a price to be paid. Inhabiting the discarded shell of a hermit crab with washboard abs in front of Brad Pitt’s ex is arguably worse than being booed by Led Zeppelin, my other peak moment of celebrity humiliation.