In Timber and Stone all of my units have morale bars. I've noticed they drain if I switch professions, however I haven't noticed any effect of them being empty, nor that they ever come back. What is the effect of morale?
At the moment, morale doesn't do anything. Eventually the higher morale they have the harder they work. Robert will hopefully be implement this in version 1.1. He has stated that this is to deter you from switching profession very often.
Edit: so there was no update for it in 1.1, but there might be in a future update.