In Chinese tradition, relationship has not been good between mother-in-law and daughter-in-law mostly.
According to the analysis of human nature, a son before marriage usually is more close to mother in every way as long as relationship is concerned. But, after marriage, the son is naturally more close to his wife, keeping a distance with his mother as a result. Then on the one hand the mother wishes her son to have a wife to last her generation, but on the other hand, she grows a hate sentiment towards her daughter-in-law in a reason she does not know why.
As far as daughter-in-law is concerned she, as a girl, married to a man of strange home and surely she will not be accustomed to a new circumstance in the beginning years. Therefore, she cannot be too happy with the member of her husband’s family which consists many people of different character.
To-day is better in situation. Many new married couples have their own separate home, not living together with mother-in-law. But, still, relationship between mother-in-law and daughter-in-law cannot be good in many ways. They may keep harmony in the surface, but in their hearts they are in a sentiment just like water and oil which can never be mixed basically.