Regardless of your opinion of US President Donald Trump, it is safe to say that he isn't a man given to conventions and traditions.
And if there is one thing that you could definitely say about the Royal Family, it's that their entire existence is coloured with - if not defined by - a staunch adherence to tradition and protocol.
Naturally, then, when they met yesterday, something had to give. Given the precedent set by The Donald over the last few days on his first official trip to the UK, you can imagine who it was that made the news.
Trump has been accused of several breaches of protocol after leaving the Queen waiting, failing to bow before her and then walking in front of her.
People were questioning whether Trump deliberately broke the complex rules of royal engagement or whether he simply didn't know them.
One incident, in which the pair were inspecting the Coldstream Guards only for Trump to walk in front of the Queen, led many to think that he did know that there was something that he was meant to be doing, but couldn't quite remember what it was.
Others on social media called out the President and his wife for not appropriately greeting the monarch.
Blimey, remind me not to forget my manners in front of Her Maj when the world's cameras are present. There's enough of a shitstorm in my house if I forget to say 'please' when my mum asks if I want brew.
Still, the sight of the Queen sitting looking at her watch when Trump was late was, in fairness, quite funny. Does she have anywhere else to be?
One suspects that the Queen hasn't planned anything else for the day of the President of the United States' first visit to Britain, although she might be worried that the 3-15 at Kempton is about to start without her.
It was a strange day for Donald Trump, all in all - he'd already been made to feel 'unwelcome' by the sight of a Trump Baby blimp soaring across the London skies, while a huge cull of inactive accounts on Twitter saw him lose 100,000 followers.
Still, you can only imagine the Queen sorted a royally impressive Maccies order to cheer up the President.