Santosh is the umbridge but here are reasons why she has obsession with Rich people.
1) in first episode she mentioned that they both married in a same status but today her sister is rich while she has become a middle class ( jealousy is the key point in her life. She is jealous how she never experienced those richness stuff. Here the character is selfish too because more than daughters it's her aim to become rich )
2) partial towards her own daughters - The actress in one interview said that her character is partial but she loves her three daughters, but first one more because she is beautiful and she feels Seerat is the best candidate to fulfill her dreams. She said Sahiba is the bread earner and here she doesn't think about her because if she will get married who will give them money ... So she didn't expected her to marry. Keerat, is her least fab child because she is rebel and someone who is ignored.
3) Doesn't respect her husband, it was bad to see how thos woman was insulting that guy. Atleast he is working not like other men who stop working. Whatever he sells he is earning some penny, instead of supporting him. She insult him, not only her husband but her middle daughter for not earning .... ( Is she an ATM ???)
4) Lie and Cheat and Blackmail
Lalach sabse buri Bala hai ...
This phrase suits on her. She is obsessed and would go to any step to make that possible. Irony is yes she did successfully executed but the outcomes was not expected, in og i feel she was still happy for clowns couple but for The leads there was some unspoken hesitation she felt.
Last but not the least, Her one lie will destroy her obsession. She will see her daughters getting ruined all three, despite marrying into rich family. Angad might Accept Sahiba but Santosh, never ....