Marge's meeting in the city with her old classmate Mike. At first, the scene seems extraneous, but when Marge learns the truth behind Mike's dialogue the next day, during a phone call from her friend in Brainerd, she has the most subtle "Eureka!" Moment and is able to look at Jerry in a different way. Noted in Ebert's Great Movies retrospective of the movie.
Jerry himself is probably going to be even worse: he's been arrested for his involvement in a kidnapping plot that spiraled into murder, he is probably looking at a decade or two in prison (unless he can get a plea deal), his wife's family blames him for Jean and Wade's deaths, his son will probably never forgive him, all of his business partners will abandon him, and when he gets out, his career prospects are less than bleak. He no doubt deserves it, but damn.
of the movie.