well, compared to the train wreck that is any relationship my brother-in-law has ever had, I'm a zillion times better. I think they keep their mouths shut about my "flaws" because of this.
If I had to guess what they may not like about me, it would probably be that I am highly opinionated, which leads to me not being able to hold my tongue sometimes with the bullshit that goes down in their house involving my brother-in-law and his baby momma and 2 young kids. I'm frustrated with all of them at this point, even as much as I love my in laws and think they are good people. That is actually their downfall - they are too nice and have allowed the situation to get out of hand because they are afraid to put their foot down/show tough love.
I also am NOT a Texan (nor do I ever plan to be) and not domestic in the least. But, again, I think they are happy that their son (who struggled a bit and joined the military out of HS) met someone who has her head on straight, went to college, has goals, isn't certifiable and isn't going to be mooching off them until they die. As I said, a zillion times better than my BIL's women