An almost perfectly balanced combination of real-life adolescent awkwardness and laugh-out-loud comedy, writer/director Mike Mills' Thumbsucker is an absolute success. Lou Taylor Pucci shines in his first leading role in a feature film with a performance that is nuanced, funny, and geared well for the camera. The young actor strikes a careful balance in his portrayal of Justin, so that while his screen presence is compelling, his struggles still remain raw. The grace with which Pucci mixes the emotion and humor in the script can't be praised enough, as this is what keeps the potentially cumbersome subject matter of a 17-year-old thumbsucker from becoming too awkward for audiences to handle. It's only too easy to see how an actor with less charisma would have left audiences too uncomfortable to enjoy the film, while a run-of-the-mill cutie-pie couldn't possibly have done justice to such understated emotional material. Pucci's ability to pull us in with his tenderness and charm is what enables us to put ourselves in Justin's shoes; his imperfect relationship with his parents comes off as both strange and universal, and while his embarrassing fixation always seems potentially humiliating, it also feels analogous to any other coping mechanism, so it's never outside the viewer's scope of relating.
The supporting cast also does a stellar job of injecting that highly necessary laughter, sarcasm, and perspective. Tilda Swinton and Vincent D'Onofrio evoke flawed but forgivable characters with the masterful skill we've come to expect from them, while Keanu Reeves approaches his role with such surprisingly self-effacing grace, you almost want to pat him on the back. Vince Vaughn takes his own road less traveled and reminds us of the subtlety that first landed him on the map, as he avoids the frat-pack comic style we've come to expect from him and keeps his performance as the eccentric high-school debate coach reeled in despite numerous opportunities to jump over the top. The beauty with which these actors engage in the poignant and infuriating tangle of their characters' relationships owes to more than just chemistry but also to an organic realism in the script itself. The resulting interplay combines the passion of an opera, the delicacy of a ballet, and the rawness of an unflinching documentary, turning what could easily have been a cringingly uncomfortable satire into something both beautiful and real.