You have the body of a hunter-gatherer but you may well inhabit the environment of a zoo.
Which is maybe why you don't feel brilliant 100% of the time.
Like the panther whose fur is not as sleek as it ought to be; like the gorilla who has lost his desire to swing on the aesthetically designed concrete and steel climbing frame, the zoo which we inhabit just ain't right. Too much sitting, too much desk and screen and artificial everything.
Sometimes you just need to walk. And stand and climb and wander and breathe some real, fresh air.
Soon your fur will glisten and you'll be ready to start swinging through those trees again.