The driving of the wedge.

Here's an interesting thing that I've noticed about this particular arc. The interesting thing that I've noticed is that we're dealing with the fact that Marian is doing the same thing Andi Fox's mother did to her back when Foxtrot was a daily strip: being a better mother, housekeeper and cook than her daughter is. Since we're dealing with a person who doesn't really see the problem because she and her husband took years to see the grown woman Elly is, we find ourselves dealing with the fact that she does what Evie does on Stone Soup and gets all dismissive and eye-rolly when it's pointed out that undermining her daughter in front of her children could constitute something of a problem. Since she doesn't have to deal with the after-effects after she leaves, she sort of fails to see the mess she left Elly to clean up.

What she also doesn't realize is that Elly doesn't take kindly to having to deal with the problem she created and wants very much to be avenged. Just as she's teaching Mike to make the mental association between his cool uncle Phil and the pointless torment of trumpet lessons, what she's doing in this arc is making the kids believe that when her parents show up, she doubles up on the discipline to not only prove to the old bat that yes, she did learn to be a good mother from her but also to drive a wedge in between Mike, Liz, April and her parents so that they don't somehow team up to destroy her.

The sad part is that she's two thirds of being a success. The Mike who called Jim crazy doesn't know sweet dick all about Jim and assumes that Marian's greatness begins and ends with being a better cook and more indulgent caregiver while Liz could barely stand to visit the old boy when he was sick. The reason that April loved the old coot is that Elly was too busy being a big shot to turn them against one another.