Serena is desperate for a child, and the flashbacks make it obvious she has been trying to be a mother for years, but WANTING a child is different from having one. She can’t handle things not going her way, she becomes cruel and unforgiving when someone disappoints her, she lashes out at anyone within reach when she’s upset, she could never handle a two year old telling her “no.” Just because she’s judgmental about the way another wife raises her baby doesn’t mean she will be any better at it, when a 4 year old doesn’t want to go to bed she will lose her shit. Also, she despises June, when that baby grows up and looks like the woman she hates (and has Nick’s eyebrows) she will be so cruel and terrible to her. Remember when she threatened Hanna?