Oddly satisfying things...
Pulling the tape off of the sides of a completed painting is one of the Best Things Ever. Not only does it represent the completion of a work but it elevates how the finished painting looks - to me anyway. I put on my up-close glasses and pull the tape slowly towards the surface of the painting. Sometimes it rips and I have to use an Exacto knife to extract the little bits. This just prolongs the enjoyment.
It goes without saying that new tubes of paint or new paintbrushes also bring joy. And, bonus points if the new paint is a colour that I have not experimented with before.
Some other experiences that I find oddly satisfying (in no particular order of importance) are:
cool, fresh, tight sheets
waking up without an alarm
watching my propane fireplace light up
an organized drawer or closet
being active in the early hours
eating oatmeal
Completing a painting is usually very satisfying. Not oddly satisfying.