If you’d care to spend ninety minutes watching a really irritating young woman get marginally less so, this movie is for you. In “Celeste and Jesse Forever,” which she co-wrote for herself and Andy Samberg, Rashida Jones (working with Will McCormack) has fashioned a character so obstinately obtuse and self-absorbed that she makes what might have been a clever twist on romantic comedy convention less charming than grating.

The picture opens with Celeste (Jones) and Jesse (Samberg) cooing and joking while dining with pals Beth (Ari Graynor) and Tucker (Eric Christian Olsen) at a Los Angeles restaurant, their childish prattle and lovey-dovey false accents suggesting that they might be blissful newlyweds. But it’s quickly revealed that he’s moved into the garage and they’re about to get divorced, though they’re still the most amicable of friends and intend to stay that way. Of course, the question at the heart of the script is whether their decision to split up is a foolish overreaction to what appears to be a pretty minor difficulty—the fact that she’s a driven success as a trend-spotter and he’s just an underachieving artist.

Still, despite their long history (they’ve been best buddies since high school) and obvious affection, Celeste and Jesse begin dating other people even while continuing to spend a lot of time together and worrying over one another’s problems. Celeste finds a likely new partner in pleasant Paul (Chris Messina) at yoga class, but also has an evening with Rupert (Rafi Gavron), a hunky male model with a high opinion of his own irresistibility. Jesse, meanwhile, finds himself in changed circumstances as a result of a dalliance he once had with Veronica (Rebecca Dayan)—a situation that sends Celeste into an emotional crisis and the movie to a point familiar from so many romantic comedies, where the union of the leads seems to have become impossible.

One has to admire the way that “Celeste and Jesse” embraces some of the conventions of the genre (like that last-act obstacle, or having Celeste’s boss, played by Elijah Wood, be her gay buddy too) while sometimes choosing to upend them. And after the disaster of “That’s My Boy,” it’s nice to report that Samberg gives a pleasant, surprisingly restrained performance.

But otherwise it’s easier to respect this attempt to toy with the cliches of romantic comedy than it is to enjoy the result. Part of the problem lies in the character of Celeste, who comes across as rather unpleasantly self-centered and (ironically for a trend-spotter) short-sighted, and the performance of Jones, who’s so intense that you wonder why Jesse has put up with her for so long. There’s compensation in the work of the supporting cast, which includes co-writer McCormack as Jesse’s advice-spouting pal as well as Graynor and Olsen as longtime friends of the couple who are now getting hitched themselves. Wood does a nicely understated turn as Celeste’s boss and Messina an agreeable one (though not up to his work in “Ruby Sparks”), while Emma Roberts brings some pizzazz to the role of an obnoxiously demanding client of Celeste’s firm. David Lanzenberg’s widescreen cinematography uses some attractive L. A. locations well, and the picture boasts an amiable score that doesn’t descend to the unremittingly bouncy formulas used so often in the genre.

“Celeste and Jesse Forever” is a wittier, more interesting example of this sort of movie than most standard-issue Hollywood product. But even in judging romantic comedies, you need a more demanding standard than that.