If one had to choose a singular mood that encompasses the entirety of this story, I would choose denial. It keeps the Best Friend from spiraling into depression at her situation and keeps the narrator from doing it for her. The trivial bits of information we receive as we read are one of the coping mechanisms they’ve settled themselves into to keep reality away. The more absurd the fact the better.
“Who cares whether or not it’s true? In my head there are bath towels swaddling this stuff. Nothing else seeps through.” -Pg. 39
These lines mean the most in the way that they show that the best friend and the narrator were trying to keep away reality so much that now she doesn’t know how else to deal. The narrator hasn’t come to terms with the fact that her best friend died. She’s coping in her own way, the way they made up to keep from falling apart.