@f7beeee8 Urge to feel that endorphine rush afterwards?  To make your body and mind get through something seemingly hard and unpleasant and find some high in overcoming it?

Once I went to 200-kilometer “brevet” on my bicycle which was something too much both for me and my bike. But soon I passed the point of no return and had to come through. When I finally got home and could let go I fell in my bed in state not so different from subspace.