As an example of this baffling trend, I can recall Elly pouting like a huffy six year old because Mira told her sight unseen that she'd decided to wear the violet color that Elly wanted to wear. Given that Elly would end up looking like an eggplant in violet while navy blue would actually make her look human, she was been done a solid; not that Elly saw it like that. Other examples of her evil evilness is not really taking into consideration what Deanna has to look at when choosing a wedding dress, micromanaging the floral arrangements and generally giving a damn what the Pattersons have to say because it's not their place to say anything.
The mystery, of course, clears up whenever you see a Patterson talking about how stubborn, irrational and domineering Mira is for not letting them do what they want. Given how often they whoop in anger, horror and disgust whenever she appears, it appears that the thing that they most want to do is totally alienate her from her daughter's life lest she cause THEIR grandchildren to suffer the indignity of being Polish. Not, of course, that they admit to being fearful bigots or anything; like most racists who live in denial, they have lots of Ethnic Friends.