I don’t want gamification but having the data is good. It would also be nice if I could set the shower to a certain temperature instead of guessing every time.
This sounds almost feasible if one feels comfortable to install a flow meter and a thermometer into the tap, and to hook it up with a microcontroller. Setting a certain temperature requires more work. I wonder whether there are products on the market for this already.
My parents used to have one with a mechanical thermostat. It was pretty simple and worked well once you had figured out your target temperature.