Daughter trying to consult with her mother - her ideal of the family hearth and women who have sufficient experience. Sometimes the advice is not limited, and daughter show excessive infantile, self-renouncing any decision - the reason it is too strong attachment to his mother and the inability to build personal relationships.
Husband wife's mother unwittingly begins to compare with my mom and comparison is, of course, not in favor of the mother of his wife. A man can be just as attached to his mother, especially if she brought him up alone. For him, a priori, all women are perceived only in comparison with his mother, which is the best. He begins to blame the mother in law in all the shortcomings of his wife, because he thinks it costs upbringing.
Mother-in-law may not approve of the choice of his daughter, is strongly opposed to her husband, making life unbearable young family. She is trying to win over the girl's father, although the test more often prefers to stay away and do not come into conflict. But if he will support his wife, the moral pressure is particularly intolerable - divorce because Tiffany happen quite often. Mother-in-law just does not take into account the fact that makes unhappy with his own daughter, she goes ahead to its goal, once again, deciding for adult important questions.
The output of these situations there it depends on the specific conditions, circumstances. One can not blame the conflict only mother-in-law, or - usually the situation "imposed" a number of aggravating problems.