Part of what’s so disappointing about Jason Reitman’s soggy, silly adaptation of Joyce Maynard’s novel Labor Day is that Reitman’s prior film, Young Adult is so impressively ragged, in a way that suggested Reitman might be moving away from the merely solid slickness of his earlier films. Reunited with his Juno screenwriter Diablo Cody, Reitman pitches Young Adult as a refreshingly non-quirky dramedy, with Charlize Theron as the middle-aged author of a faltering children’s book series, who heads back to her dinky Minnesota hometown to seduce her married ex-boyfriend (played by Patrick Wilson). The plot is way too contrived, but Theron is entertainingly prickly, and Reitman and Cody seem less interested in hitting any romantic-comedy beats than in digging deep into the feelings of the main character: her painful adolescent memories, the comforting melancholy of singlehood, and what it’s like to live in a world dominated by chain restaurants and big box stores. Young Adult isn’t as smooth a ride as the relatively breezier Juno, but it’s more committed to being truthful, even when it hurts. It airs on Epix at 6:20 p.m. Eastern.