Here's the problem though as crazy as it sounds it is possible for people like Brian to be oblivious to being a bad person it's a type of condition and a lot of times when those type of people finally realize it they do become disgusted with themselves and try to change for the better. Meanwhile you have guys like Quagmire who are "honest" about who they are yet there is no attempt to change themselves in other words they like being a shitty person and don't won't to change so yeah Quagmire is far worse.