20:45 here. Agreed PPs! The arbitrary favoritism is the worst. It unfortunately carries over from the parents interaction with their children. One or two children get assigned the "practically flawless, beyond amazing and can do no wrong" label of some sort, only to carry over to the innocent grandchildren (mostly because the "super-children" turn out to be anything but).
MIL is like this. It is both extremely sad and extremely humorous to see her literally (no exaggeration here) jump for certain children and their spouses. She is only handicapping them, she has no idea. If she really loved the "favorites" she would not have favorites, thus handicap them so much!
Lets just say Karma truly is a bitch - moreso than MIL, if that is possible
We live closest in proximity (5-10 minutes) to MIL, and she literally drives right by the house to do other non-mandatory and social things, so she has no excuse and everyone knows it. She's just a miserable person, which most people see when she is around a non miserable person (she lashes out, its really weird). You know, maybe we are better off without her.