I thinks it's probably down to two things. Only if you don't match values and you take their child from them. Any mother is overprotective of their own, and wants the best for their child.
Not sure on this one , my mum gets along well with my wife (adds sarcasm) but they do have certain misopinion . It honestly depends with nature of family you live with where mother is matriach of their family and everyone expects to listen her , daughter in law is like rebel in the family they tend to follow their own rules or expect husband to support her .