Marge and Bart episodes are so great in general for much the same reason Lisa and Homer episodes are so consistently strong: the two characters are clearly opposites in so many ways, yet there’s always a lot of love and respect between them. There’s a small thrill that comes every time the two find themselves on the same page about something, because both they and the audience understand that these moments are rare and fleeting.
It also helps that, just as Lisa’s there to speak reason to Homer and talk him down from his more crazy, unhinged behavior, Marge is the angel on Bart’s shoulder. As TheRealJims once put it, “Marge is the only character on the show that Bart consistently takes seriously. Homer’s a joke, Lisa is his dorky sister, Maggie’s a baby, but he’s had enough run-ins with Marge to never underestimate her.”
On Marge’s side of things, Bart shows just how unconditional the love for her kids is, as she never stops trying to spend quality time with him, despite his opposite temperament and disinterest in hanging out with his mother in general. Bart will always be a troublemaker, something the fairly goody-two-shoes Marge has never quite been able to relate to. But she never stops seeing the best in him and still loves him the way he is, to the point that the idea of him changing at all terrifies her.
“A Mid-Childhood Night’s Dream” gets to the heart of this dynamic, and reminds us that, even after 35 seasons, there’s still fresh, compelling material for these characters to deal with. Bart might not ever grow up for real, but Marge’s dread over the idea gives us one of the strongest “Simpsons” episodes in years.