Why? My MIL behavior

Feb 2021
Now that I have known my MIL for decades I realize some things I don’t understand about her behavior. Btw, she is a well off, retired medical professional with a masters degree.

My MIL has 3 children. She likes best the one that dislikes her. My MIL dislikes the child that respects and likes her. She has 6 grandchildren. She likes the two that absolutely despise her. She seems indifferent toward those that do like her. She has two rental homes. She dislikes the tenant that pays timely and takes care of the house. She likes the tenant that pays late, damages the house and is always complaining to me how much she dislikes my MIL.

Of course, my husband and I do not tell her that special child, special grandchildren and tenant cannot stand her. I am sure she is not aware because the child, grandchildren and tenant in question are polite to her face, but I am so curious how or why my MIL seems to prefer people who cannot stand her.