Energy.

Nothing has as much energy as a 7year old at 3pm on a Friday. She played on the school trim trail. Then she played table football. Then she played on the tyres. Then she scooted to the next park and played some more. Then we got home and she played still more in the garden. She's now just about asleep, excited about an all-day playdate tomorrow whilst the Mister and I are on separate training courses.