Recently, you opened your program talking about mother and daughter-in-laws' relationships. I believe the reason friction exists is because of feminism.
In a time where disdain for husbands is a commandment in the feminist bible, a woman's son is about the only man for whom a woman's love overrides her disdain.
The biggest 180 on record was my mother's change in attitude towards wives respecting their husbands that occurred when I got married. Growing up, my mother all but ruined my dad's life through disrespect and angry dissatisfaction. Spending hours a day with female coworkers where criticism of husbands dominated most discourse, it was dogma that husbands deserved no respect. Not surprisingly, my mother did not get along with her mother-in-law.
Flash forward to my marriage. Now that her son is the husband, suddenly my mother has a completely different view on the respect husbands deserve. My wife treats me exponentially better than my mom did my dad, yet to my mom, it is still not enough.
Perhaps the question that should be asked more often is, "What would I think if it were my child?"