Consequences

Become a teenager, have a summer growth spurt.
Grow fast, lose track of how long and large your limbs are.
Lose track of said limbs, bump into stuff.
Bump into stuff hard enough, feel wonky for days.

But if you don't tell your Mum or Dad about cracking your head on a door lintel till 2 days later when the world starts tipping sideways whenever you move your head, then a trip to the medics is almost inevitable.

Concussion, but mild, thank goodness.