Plot summary
Peggy announces that she is retiring, and Molly organizes a party for her. She goes to the school to invite some fellow lunch ladies, and learns that Peggy didn't retire, she was fired. While Mike first insists that they go along with Peggy's lying in order to keep the peace, he eventually gets fed up with her and lashes out by telling her "you're bitter and toxic, and that's why nobody wants you around"; Molly then reaches out to Peggy about the virtues of sometimes admitting to being wrong.
Credits
Adapted from Wikipedia contributors, Mike & Molly season 5. HTML formatting and reference markers removed.