concerning your ankle,
A joke is when the standard reality you are expecting is suddenly confronted with a strange event that forces acceptance of a new reality.
So you were repeatedly expecting your ankle/leg to function in the same old way, and your inability to make it move, and the funny (perhaps gross) way it was bending, forced you to abandon that old reality, again and again.
You are not too weird because it was you who had the strongest expectation that your foot would move in the same old way, so it was really only you who had the set-up for the joke! It was also you who had the punch line. Think about how only your friend finds it funny when his hand is asleep from sitting on it.
our humor response is triggered by “unserious threats”. I.e. your ticklish spots are in pretty dangerous spots on your body, but the light touch is “unserious”. Same for jokes: the setup of a joke presents the “threat” and the punchline will establish the “unserious” quality (matter of fact: when we perceive a joke as in bad taste or offensive, usually its because the “threat” isnt made “unserious” enough for our social views).
Hurting ourselves in ways that arent particularly debilitating follows this same scheme — the injury is a “threat” but if its not debilitating, you may be perceiving it as “unserious”, and so you laugh.
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