Why my bf`s mom always hates me?

I never met my bf`s mom but she always hates me. Why is it so? So many girls are suffering through this condition? But you ever thought why always a woman hates a woman ? What is the reason behind this ? Why you hate someone when you don`t know them. Mother in law hatred towards her daughter n law is a tradition or custom. But what you call this condition;meant by bf mother hatred towards his son`s gf. So many answer suits it. Like she hates son`s gf ,if he is student then gf is totally unbearable. But if he is not a student then gf have no more place in his son`s life. Gf is a viral disease if it would not cure at time, it must prevail and destroy whole body.
She says she trust his son but she have fear may be he chose wrong girl. One of my aunty hates gf relationship; once she told to my mom I know so many girls are around to my son . But I told him earlier, do whatever you want but you have to marry the girl that I chose. So she indirectly dragging him to wrong relationship. This type of rigid thinking is very common in Pakistani mother. If you nourish your son so why shouldn`t trust your son? Why always a girl bad why don`t you blame your son first? Your son who hurts your feelings and trust . Why you always blame gf. You even reject to meet or talk to his gf? Why? I think all bf`s mothers is afraid of girl friend’s phenomena . I think this suspected feeling of bf`s mom is fall in paranoid condition. All bf`s mom is suffering through paranoid condition (baseless or excessive suspicion of the motives of others). And she hates most, the message ringtone that rings on every 15mins on her beloved son`s cell. If the gf call bf cell, accidently if bf`s mom receive the phone, gf starts talking then she give her a award of cunning girl . If she immediately turns off the cell then she called her ill mannered. Also said I can`t understand now a day’s girls? They even don`t care their poor parents.
Why is it so? Also she don`t even hesitate to complaint gf`s parents about her innocent deed. What is her crime? She called to your son because he also talks her, he also loves her. Why always a girl blame for this. why don`t you understand sweet bf`s bitter mom I am not clever, I respect you because you are my lover`s mom. But why not you show generosity , I am not spoiling your kid. Very few sweet mom`s are also be there, who support their son and his gf too. But the former type of bf`s mom is seen everywhere.
In the nutshell, I only want to say girls stop roaming around boys. Because they never give you a respect that you deserve. Also not able to defend you from their mother`s anger. The psyche of boys is always remain same as before 20`s or in 2012. They left you , they blame you for every failure in relationship but never accept their mistakes. And please stop defending yourselves like starplus daughter n law for what deed you even not heard. Also for boys’ mother, boys are only one who first come following the girls like honey bees. Also trapping sweet girls in different ways. Your son got another girl that you chose but what about the poor girls, who love your son with full sincerity. Moreover, if her future husband knows about her ex- relation then he immediately kick her out from his life. So this all about the bf`s mother hatred result.