When security fears are heightened, it makes a humourless age even more humourless - which the British embassy in Washington has just learned.
Yesterday was the 200th anniversary of British soldiers burning down the White House in 1814, during the confusingly named War Of 1812.
To celebrate, London's people in Washington served a massive cake, complete with sparklers, fanfare and a Twitter picture.
They joked they were using "only sparklers this time!"
But, as news of Islamic State jihadists threatening death to the West and murdering people dominates the headlines, it was perhaps not the best time to cheerily joke about Redcoats marching down Pennsylvania Avenue and destroying the president's home.
This guy was distinctly unimpressed.
And, in a sign that tropes of British political culture have made it across the pond, this guy blamed the Tories.
"Apologies for earlier Tweet," the embassy said. "We meant to mark an event in history and celebrate our strong friendship today."
It might seem odd "celebrate" a "strong friendship" by recalling the time you burned down your friend's house, but oh well.
Some found the whole thing hilarious.
But a lot of people were unsure why the embassy felt it had to apologise.
One person suggested the embassy's only crime was getting "good at Twitter".
One American hit back (sort of), by cruelly claiming Britain's timid need to apologise for everything was why we lost the War of Independence (not the War of 1812 obviously, that was a draw).
Not cool, Blake, not cool. We're not holding our breath for an apology though.