We should make the happiness bar actually useful!
If the happy bar is full your character should gain learning points at an accelerated speed, like an extra 10 ~ 50 % depending on how happy he is. But if he is unhappy he should lose stamina much faster while doing shitty tasks like removing stumps. The bar should drain much slower then it does and it should have a few other ways of getting yourself happy. This way the bar actually has some use instead of just sitting there in the UI going " Lol look at me, Im a bar :3"