So you have been for a run (walk, cycle, garden) in the cold (and/or rain, snow, precipitation of your choice).
You are just a teensy bit smug because you have, and you didn’t listen to the sofa-demon calling you. You are also just a smidge chilled because you faffed around for a bit when you got in; you checked your mail or boiled the kettle, uploaded your Garmin or (weirdo) cleaned your shoes.
So you run a bath or start the shower, and jump in. And there is that point when the temperature is just right, a little bit too hot so that it makes you shiver, but not so much you have to jump out. And at that moment when the nasty cold is replaced by the tingly-tickly warmth is the best feeling in the world. And it is pretty much free and very legal, aren’t we lucky?