Ebb and flow of energy

I'm struck by the fact that children can have little to no energy and within 15 minutes they can be the Energizer bunny. CamMad is a prime example. Today CamMad at separate points were down for the count but rebounded with the energy that comes with youthfullness. I can only speak about CamMad but the transition time is scary for those who are around them. Today I was the only victim. Usually the transition time includes screaming, tears, kicking, and flailing. Sheepish this is not a time when I do a theraputic hold, car seats can serve that purpose. Every time CamMad goes through this process they come out much better and fun to be around. If it only worked that well for adults...