The Right Beat Of The Wave
Why the timing is the joke, not the leaving.
Why it is not the leaving: the thing is going to go either way - that is not in the joke. The joke is what you do about it. A scared face, a sprint, a plea - those are all reactions to the loss. The squirrel wave is the one that treats the loss like a small, expected thing. The calm is not denial. It is the move of deciding, in the last beat, that the thing can go and you are still you.
The three beats: too early is eager - you wave before the thing is even committed to leaving, and it reads like you are waving it away, which is not the gesture. Too late is gone - the thing has already passed and your wave is just flailing at air. The right beat is the calm one, in the middle, where the thing is clearly going and you are clearly still there, and the two happen at the same time.
How the game tests it: each round gives you a line - a goodbye to the thing that is leaving. You read the beat and press the wave button. The page scores how close to the middle you landed. The whole skill is not speed - it is the refusal to rush the leaving, and the refusal to be late to it.