The Rambam paskens that having good middos is a mitzva from the Torah [as we discussed at length in a recent shiur].
He paskens elsewhere that one need not only do teshuva for evil deeds but for bad middos as well.
But that would seem pashut. Just like evils deeds are aveiros and one needs to do teshuva, so too bad middos are inherently sinful and one must do teshuva. So what is the chiddush?
