Something has occurred to me and it might be from left field in a galaxy far, far away but I wouldn't be one bit surprised if Trump was even a little bit intimidated by the presence of the Queen. We've seen how he is and how he interacts with those on the world stage today but those people aren't HM, The Queen that Trump has known about since his childhood.
Many, many people have remarked that upon meeting the Queen, they've been at a loss for words or at a loss for what to do. Just her presence can make some feel like they're schoolboys being sent to the principal's office. I wouldn't be one bit surprised if this is what happened with The Donald. He's met his match even though he outsizes her by quite a bit.
I hope he can and does pick up some lessons on diplomacy from meeting what may be the most iconic head of state on the world stage today. If he's noticed that over her very long reign, she has never put a foot wrong, perhaps he'll realize that this is a woman that knows her stuff and has been at it since he was a kid, perhaps he can in some ways, emulate her.
I figured that the Trump entourage was running late when we saw the Queen glancing at her watch and just standing there waiting and waiting and waiting. That was a faux pas. Usually these things are planned and executed right down to the minute and one doesn't keep the Queen waiting. Hope she chastised him good and proper over tea about being late.