Zach Braff’s sophomore follow-up to his overrated debut “Garden State” begins badly with an ungrammatical title, but immediately tops that with an opening scene so terrible that it might make your jaw drop in appalled amazement. And while it gets marginally better after that, it never becomes anything more than an anemic sit-com leavened with heavy-handed doses of mawkishness. “Wish I Was Here” will make you wish you weren’t.

Braff, who co-wrote the script with his brother Adam and directs it as well, stars as Aidan, a wannabe actor who can barely make it through an audition, let alone land a role—but won’t give up his dream. That leaves it to wife Sarah (Kate Hudson) to be the family breadwinner, though her office work requires her to put up with a sleazily sexist co-worker (Mark Thudium). And it’s help from Aidan’s father Gabe (Mandy Patinkin) that finances the cost of private yeshiva school tuition for their kids Grace (Joey King) and Tucker (Pierce Gagnon)—which Aidan’s happy to accept even though he’s not observant himself.

Problems arise when Gabe announces that his terminal cancer requires him to spend all that he has left on a costly experimental treatment and can no longer foot the kids’ school tab. That forces Aidan to begin home-schooling them, though he’s singularly ill-equipped to do so and seems to spend little or no time on instructing them anyway. Instead he’s going off to auditions and dealing with Gabe’s illness while trying to get his reclusive brother Noah (Josh Gad) to leave his trailer and see the old man, and day-dreaming about how as a kid he imagined himself as a courageous space knight fighting all sorts of evil creatures.

This is one tiresome brew. Aidan is meant, one supposes, to be a charming, well-intentioned but hapless schlub, but as played by Braff he comes across as a narcissistic jerk, whom Braff the writer heaps with purportedly funny lines while Braff the director, with the connivance of cinematographer Lawrence Sher, makes him the absolute center of this cinematic universe. But he’s not the only irritating character on display here. The two kids—oh-so-orthodox Grace and troublemaker Tucker—are almost as tiresome, and as Sarah’s loathsome colleague Thudium is very nearly intolerable. Gad’s Noah is only slightly less annoying than Braff’s Aidan, a caricature of genius-level arrested development, and Hudson is pretty much wasted as Sarah. Even the two rabbis (Alexander Chaplin and Allen Rich) are crudely treated for some cheap jokes, and Jim Parsons’ brief role as another failed actor is of sub-sitcom standard. The only person who emerges with his dignity unscathed is Patinkin, who underplays nicely even though his scenes as written are hopelessly maudlin.

There’s a shambling, episodic quality to “Wish I Was Here” one might justify by arguing that it reflects its auteur’s personality, which was the saving grace of “Garden State.” But this time around Braff seems incapable of coming up with anything but tired gags about swear jars, video games, comic-cons, first dates and test drives in expensive cars. And he’s totally unable to create a character you even like, let alone sympathize with. Even an accomplished comic actor working with a skillful director couldn’t make the Aidan of this witless script engaging, and here one finds neither. Sher’s camerawork isn’t impressive either, though as with his previous picture Braff has given great attention to the songs that serve in the background, so the soundtrack may be of interest to some listeners.

“Wish I Was Here” was partially funded by one of those Kickstarter campaigns in which ordinary folk become small-time investors in a film. After seeing the result anybody who shelled out their hard-earned cash in support of such a vanity project might feel like kicking themselves in the rear if that weren’t a physical impossibility.