The Queen dutifully sits through hours of displays of military pomp rehearsed to the second - and secretly loves it when everything goes wrong, Britain's pageant master says.
Major Sir Michael Parker, who has spent 46 years producing grand events, told the Daily Telegraph the sovereign is most amused when showpiece spectacles descend into calamity.
Parker, 71, has produced more than 320 events including the 80th, 90th and 100th birthday celebrations for the Queen Mother, plus Victory in Europe and Victory over Japan anniversary celebrations.
Parker recalled the 1977 Silver Jubilee beacon-lighting in Windsor Great Park, west of London, which was his first national spectacular.
He had stuffed the beacon full of fireworks as he worried it might not catch light fast enough.
The Royal Signals major positioned to press the detonator had done so prematurely, with the fuse lit by the monarch still fizzing about 60m away.
"Can't think why you bothered to ask me!" she had said with a laugh.
The sound system had started to fail and a deafening firework mortar had gone off instead of a flare.
Parker explained: "'Your Majesty', I said, 'I'm afraid it's all going terribly wrong'. Her face lit up. 'Oh good,' she said. 'What fun'!
"I feel sorry for her, having to watch so much dreary stuff all the time. Anything that keeps you awake and makes you smile must be a good thing.
"The Queen is always amused by cock-ups, as long as they're not serious. Most people would not notice the things that go wrong.
"She doesn't miss a trick," said the 71-year-old.