One of my favourite childhood memories comes from being taken round Windsor Castle for the first time by my father, when I was about 6 or 7 years old. My dad walked off to get us drinks and left me staring at the first in-the-flesh Royal Fusilier I had ever seen, with silly bear hat and everything.
I had a toy soldier with exactly the same outfit and I was amazed at the fact that this actual human being could be as still, maintain the exact same pose, and remain as motionless as the figurine. I remember being very impressed.
In front of the sentry boxes that they stand in, there is a yellow line on the ground at just over bayonet range. There is a big sign basically saying “do not cross this line, the guards are armed and will kill you if you threaten them.” Despite this, one slightly-older-than-me child was taking great delight in putting one foot over the line, putting his hands to his ears, blowing a raspberry at the guard and then stepping back over the line to safety.
After about a minute of this, the guard (who had remained motionless and impassive the whole time) finally belted out, in his finest drill sergeant voice:
“IF YOU STEP OVER THAT LINE ONE MORE FUCKING TIME, I WILL SHOOT YOU IN THE FUCKING HEAD.”
And then snapped immediately back into statue mode.
Silence descended on the courtyard. The child looked up at the soldier with a loaded rifle that he had been trying to annoy, realised exactly what was happening, burst into tears and ran away.
There were a lot of muttered sounds of disapproval but I swear I saw the guard crack the briefest of smiles. This was a few decades ago but even then, I heartily approved.