Margaret is the overbearing rich boss of Flying John. All she truly cares about is her dog Foo-Foo. She never allows John to have any fun although he desperately wants to. Foo-Foo doesn't like John either, as she is shown growling at him whenever Killjoy Margaret scolds him.
Margaret, her dog Foo-Foo and John are the last people seen leaving an upper-class apartment building. As John starts to play on a hopscotch board, Margaret scowls at him to stop. Later on, they walk by a peanut stand where John stops to interact with an organ-grinder's monkey until Margaret pulls him away, much to his chagrin. They go into "Le Pampered Pooche" pet store where Margaret picks out multiple items for her dog, throwing each one to her husband as she does so. As they make their way home, they pass by the construction site where Joe has just received a job. As he lowers a hook toward a pail of nuts and bolts, a pipe pushes the hook into Margaret's path, resulting in her and her dog getting hoisted into the air. Upon noticing that she is gone, John decides to go to the jazz club's talent night and finally have some fun! Meanwhile, Margaret angrily tells Joe to let her down but he is too happily engrossed in his work to pay her any mind, leaving her stuck on the hook in anger and defeat.
- Killjoy Margaret is very similar to the Wardrobe, both in appearance and personality.