After unequipping the crown once, when you try to equip it again, you only gain the bonus and you can repeat that for infinite bonuses.
I don't know if it's a bug or just not implemented, but I can't get past muscle level 1 : working out just gives nothing.
It's easy to abuse RNG when you sell yourself : if the hour passes uneventfully, you can just rewind and try again (that's not a bug, but it could be improved)