The concept of Quitting is much more interesting than the film itself. All the "actors" in the film are actually just playing themselves. The story is based on the true-life washout and redemption of actor Hongshen Jia, who was a B-grade actor in Chinese action films of the 80s and 90s. By the time Hongshen reached his 30s, his life had spiraled into a vortex of destructive drug abuse, causing him to screw up not only his professional career, but also his relationship with his family (mom, dad, and sister, all playing themselves).
We meet Hongshen as he has finally accepted an offer of help from his retiree-aged parents. Moving into his parents' apartment after leaving detox, Hongshen mopes around, pouts a lot, is moody, and is basically an insufferable brat. Keep in mind that this guy is 30-something. After watching his emotional (and sometimes physical) abuse of his parents, I wanted nothing more than to give him the good, swift, kick in the ass that he'd been needing all along.
Substance abuse is a tricky topic for any film. Is the film asking us to be sympathetic? Should we hope for the redemption of the troubled son, as the parents fervently hold out their hopes for? Unfortunately, with the sluggish pace of the film, and with the absolutely intolerable behavior of the lead character, Quitting doesn't earn the sympathy, much less keep the interest of the viewers that it hopes to educate.