When I was about ten or so, I developed an odd little game. A friend of mine would stand on the school playing field with their eyes closed. I would then stand next to them and explain that they were in fact standing on the very edge of the roof of an immense skyscraper. I would then describe in great detail their surroundings, the wind whistling around them, the dizzying height in front of them.
And then, at the very height of their absorption in the story, I would give them a good hard shove in the back.
Now, twenty six years later, I'm doing exactly the same thing for a living.
And now, as then, it's all about deciding when to shove.