Nothing, she has nothing, well that's not true she has selfishness and a lack of understanding on how to be a good mother.
Her coming back is not even the most annoying part, the most annoying part is that she's gonna come back and
they're going to take her back! Hell, with how Dean is about family, the pedestal he had her on and the issues he's got I wouldn't doubt it if he tried to defend her and blame himself! Which is gonna make me all
with the writers and Mary and all
for Dean.