IDK, compared to the other Bluths he was the straight man, but Michael has always been kinda goofy and an a$$hole.
Even before this season, he never listened to his son, treats Ann like shyt, messing with Marta when she was still with GOB, tried to pimp Lindsay out to Uncle Jack, getting into fights with GOB all over, trying to teach his pops a lesson, setting the banana stand on fire with the intent to collect the insurance money,
Also, Lindsay told him that he had a false sense of superiority back in the earlier seasons.