A lot of people work sitting down, though it’s not often in public apart from those beavering away at laptops in coffee shops. Anyway, wherever they are working the opportunity to drift off for a few moments is probably a luxury. Stewards – or guardians, custodians, invigilators or whatever they are called – professional sitters, in museums, galleries and historic houses appear to have plenty of time to take a moment. It must be difficult not to take a nap. Photo: National Archaeological Museum, Athens, June 2019