Eva always refers to the day of the massacre as that Thursday. It is the day all of her fears about Kevin come true. She is vindicated in her suspicions, and his derangement becomes public knowledge after the tragedy. Thursday is also the day on which Kevin enacts his ultimate revenge on Eva; he kills Celia and Franklin—the two people she loves most—and leaves Eva alive. Thursday guarantees that if Eva wants to retain anything of her nuclear family, she and Kevin will be the only options for each other.

Even as a toddler, Kevin prefers salt to sugar. He is able to make more messes with salt, as shown when he sucks the cheese doodles and then leaves their soggy remnants on the seats of their vehicle. By eschewing sugar, the author reinforces the fact that there is nothing light or sweet in Kevin. It is also another way for him to set himself apart from the masses. Most people can find salt and sugar enjoyable, even though they might have a preference for one. Kevin never even pretends to enjoy sweetness.