I have a great set of in-laws. They nicely complement our family dynamics, and as noted above, I would have never married Chris if I didn't like them. Especially Dawn.
At a very young age, I clearly remember thinking that I had to like my boyfriends mothers and she truly like me, or there would be no hope for the relationship. Some people will marry their spouse because they don't really care about the anything but that person, but I HAD to care about the people that raised my husband. I didn't want to think about how upsetting my in laws were, how the imposed on our family, or then mean things they may say, etc.
Thankfully I haven't had to worry about it. I was blessed with clairvoyance on the in-law situation. They have been wonderfully supportive, and are wonderful grandparents, even if they do things differently than what I or my family would do, especially when it comes to voting :)
I also realized while posting this, besides birth pictures with the kids, I don't really have enough of pictures with their grandparents.... hmmmm sounds like we need to bring the camera to their house.