"but any joy you had in making music will have long since been driven away"

The trick to coping with 'Hanon' is to learn to meditate while playing - to allow your body to perform the physical exercises correctly while your mind remains calm and can multi-task. The same trick works for scales and arpeggios.

The result is that you are better able to function in ensemble work, because you are not so absorbed in just yourself, and more able to listen to and respond to what is going om around you.

It also strongly helps combat "stage fright".

This may be one concrete difference between 'classically-trained' and 'self-taught-folk' musos...

:-)