Collapsing the expansiveness of book characters into quickly understood film characters involves trade-offs and compromises, kind of like chopping off your limbs in order to fit into an American Airlines coach seat. The flight is less cramped, but all the arms and legs that made you into such an interesting jazz dancer are gone forever. The conversion of Peter Cameron’s novel Someday This Pain Will Be Useful To You into director Roberto Faenza’s film must have been pretty brutal, because these 2-D characters might as well be wearing T-shirts that say things like “Predatory College Professor” and “Self-Obsessed Father” on them. James Sveck (Toby Regbo), the film’s Disaffected Teen, is a smart kid resisting the desires of his parents and trying to create his own identity in the summer after high school. James, like everyone else, lacks any tangible details that elevate characters from familiar movie templates to actual, believable people. Ellen Burstyn plays Nanette, James’s grandmother, one of those cinematic holy saints who exist solely to extrude serenely inspirational pearls of nonsense about life, and how life is all around us, and we have to live and love and dance and shit like that, and then die. Instead of the italics in the previous sentence, pretend that’s all written in a MySpace sparkle font. Her T-shirt would say “Bullshit Yoda” on it. Burstyn is great, but what the hell else is she supposed to do with this flat, trite pile of serene aphorisms?