I remember participating in a study for a friend of mine where I had to go into a cryochamber and I remember 2 very distinct things
1. How warm -60c felt after walking around in -130c for a few minutes in just shorts and shoes.
2. How much I wanted to run once I got out of the chamber. I was not a runner and I never liked running but I really wanted to run.
I kind of want to do it again to feel that high. Cold showers got a smaller reaction but something similar.
I need to get back into cold showers again but I definitely felt best when I was doing cold showers, it's a cheap trade of a few minutes of unpleasantness for such a mood boost but it's hard convincing yourself to do it first thing in the morning though.