@literorrery Pain-induced endorphins. I have a lot of tendons in various states of inflammation right now, and the best treatment for that is to force them to stretch out to full length... which is, frankly, horrible. But there's a bit of a little subspace-displace-headrush after that's almost enough like 'reward' to do another one. And another. And another.
It improves the odds tomorrow will be better.