Happiness can change your first and second nature
ב''ה Happiness has the ability to change your second nature, habits you have formed and other things you do regularly. The reason for this is that happiness is a "giluy hahelem of the neshama" - revelation of the hidden state of the soul. Happiness can also change first nature, essential inbred traits can be overcome by a state of joy (at least for a short while.) Happiness is able to acomplish this because it is a - "romemut of the etzem hanefesh" a exalting and lifting up of the inner essence of your soul. Mittler Rebbe - Drushei Chatuna Beit - Samach Tesamach harishon