And it's a very relevant lie. She "saved" Missy's life, but like many mothers, she sees what she's done out of her lens. Yes, she "saved" Missy's life, but found her and all her children ungrateful for her "sacrifice." To her, Missy spent the rest of her life acting up, so she always had to have her thumb on Missy's "antics. To her, that was taking care of Missy. Only once did she realize that she'd been ignoring Missy, but aside from allowing Missy to choose the restaurant finally, that awareness didn't hold against the tidal wave that was Sheldon. How do I know this? Because no matter how deeply I loved my first born, I did the same thing to him with my daughter, born with disabilities who took all my time and energy. It was brought up to me and I just couldn't see the damage I was doing. Mary didn't so much lie as she was unable to see from a different lens. She was "christianizing" so hard to "save" all her children that she forgot all of them needed HER, not just Sheldon. When Sheldon finally left and Missy finally left, she finally had time for Georgie.