A grating protagonist alone does not a bad film make, but the episodic, unsatisfying Lemon revels in purposeful nails-on-a-chalkboard unlikeability. Isaac (Brett Gelman), a struggling actor and stage director who is also platonic ideal of the pseudo-hipster schlub, spins out of control after his girlfriend (Judy Greer) leaves him. Another film would make the ensuing tale a mope-fest, but Lemon veers toward strident weirdness with minimal payoff. Your enjoyment of the film is likely to be highly dependent on your tolerance for the comedy of discomfort; fans of the prickly humor seen on Adult Swim (where Gelman cut his teeth) should be well served. (Also, fans of literal toilet humor: A scene of Isaac farting loudly while he sits on the stool for what feels like ages is chuckle-inducing at the basest level, but more likely to lead to eyerolls.) Some of the uncomfortable moments at least play out with a certain amount of formal daring. But the comeuppance Lemon has in store for Isaac doesn’t really make up for the callousness of a line like that.