Why the animosity between MILs and DILs?
My theory: Some mothers are very emotionally vested in their sons.
Somehow this is not as much an issue for fathers and sons-in-law. I think that is because fathers, typically, do not invest as much emotional identification into their daughters as mothers do into their sons. I posted the rest (with both Biblical and literary quotes) at http://www.examiner.com/examiner/x-18522-NY-Jewish-Bridal-Examiner~y2009m12d24-No-woman-is-good-enough-for-my-son
Somehow this is not as much an issue for fathers and sons-in-law. I think that is because fathers, typically, do not invest as much emotional identification into their daughters as mothers do into their sons. I posted the rest (with both Biblical and literary quotes) at http://www.examiner.com/examiner/x-18522-NY-Jewish-Bridal-Examiner~y2009m12d24-No-woman-is-good-enough-for-my-son
Comments
http://divreichaim.blogspot.com/2007/06/eiruvin-86-volatile-family-mix.html
You do see a MIL DIL relationship working out with Ruth and Naomi, though the former really had to take complete direction from the latter. But it is an interesting point, I find, that none of the immahos are ever shown with their MIL's. Sarah died before Yitzchak married Rivka, and Yaakov's wives never met his mother due to the distance between the households during her lifetime.