There are so many mother-in-law horror stories from around the internet that there's a whole subreddit dedicated to it. It's a classic gripe, the whole Meet the Parents franchise of movies is based around the phenomenon of hating your in-laws. But it's classic for a reason. Family who's not quite your family but acts like your family… that's a tricky relationship. You want to include them in your life because you love your S.O., but setting those boundaries in the right way is a tough gig. And people love to push the limits of your personal life when they feel they're entitled. Most folks just grin and bear it if they have the luxury of not seeing their in-laws that often.
Of course, things get more complicated when there are kids involved and you live close by. That's the driving force behind this recent Reddit story that exposed the nefarious dealings of a real monster-in-law.