I understand what you are saying and I have seen those kind , I was very young though , never had to face it. My sister is happy she did not face that either , her MIL and SIL adore her.
Just to put some smile on your face visit this thread:
You will find out that it is a universal phenomenon, not limited to desi world.
http://www.blubet.com/bet/How_to_kill_your_mean_mother_in_law