Late one Friday night in the year I left university, I woke on a strange and distant railway platform, lying face-down in a puddle of my own yeasty vomit – half-chewed chunks of pineapple strung in my hair – and resolved never to regret another choice. Since then, I have applied myself assiduously to leading a blame-free life, fearing guilt, and retreating from any situation that might lend itself to my own embarrassment or shame. Time and again, I have been reassured that regret is little more than the destructive byproduct of an inconstant mind.