There is exactly one unexpected moment in the otherwise drearily predictable The Five-Year Engagement that, though little more than a throwaway line, at least adds a bit of charged political reality to puncture Nicholas Stoller's limp, hermetic comedy of deferred nuptials. Tom (Jason Segel, who co-scripted with Stoller), a talented sous-chef at an upscale eatery in San Francisco, tells his lez boss (Lauren Weedman) that he's quitting to move to Ann Arbor, where his fiancée, Violet (Emily Blunt), has just been accepted to do postdoc research in psychology at the University of Michigan. The head chef snorts at what a bad decision Tom is making in the name of coupled commitment before dropping the bomb: "This is why I voted against gay marriage. Please don't tell anyone I said so."

A gay person's (or any person's) anti-knot-tying stance — as an actual principle, not commitment-phobic skittishness invariably cured in the final act — tied up with the wish to keep that belief closeted would make for a great romantic comedy. But those complicated emotions have no place in The Five-Year Engagement, a film as comfy and cute as the bunny costume Tom wears at the New Year's Eve party where he first meets Violet. The movie opens on their one-year anniversary, the night Tom proposes. They postpone the wedding so that they can get settled in Michigan, an adjustment period that involves lame gags with snow and ice and the lack of classy restos worthy of Tom's skills (which never seem to involve much more than onion chopping). While he makes Reubens at Zingerman's deli, Violet thrives under the academic mentorship of Welsh charmer Winton (Rhys Ifans). When her postdoc is extended, Tom's deepening misery at being stuck in the Wolverine State takes the form of extravagant facial hair and an obsession with crossbows and deer meat; the downward spiral continues, culminating in extracurricular drunken kisses, an amputated big toe, and the couple's decision to call it quits.

With about 45 minutes to fill before the preordained conclusion, The Five-Year Engagement introduces one amusing minor character, Audrey (Dakota Johnson), a decade-younger hostess whom Tom starts dating — and who erupts into ageist invective when he delivers news that she doesn't want to hear. Some of that fire might have made dully cheerful Violet a more memorable creation; her most outlandish act is to quietly suggest to Tom, "Maybe it's okay for me to be selfish," after breaking the news about her continued academic funding. She's an improvement over the vindictive shrew Kristen Bell played in Forgetting Sarah Marshall (2008), Segel and Stoller's first collaboration — which, like this film, was also produced by Judd Apatow — but Violet remains a strenuously anodyne character, one that not even a performer as gracefully instinctual as Blunt can do much with.

The loutish or regressed guy behavior that typifies Apatow productions has also calcified into the innocuous. Segel is pants-less twice, though the shots are full-dorsal, not Sarah Marshall's full-frontal; Tom's male friends, with their pillowy, carbed-out bodies, are devoted, doofus dads who giggle over naughty wordplay.

Occasionally, the dialogue in The Five-Year Engagement might sound like something an adult audience member has once thought or uttered. "I wanna be alone with you here," Tom pouts to Violet after they've had a fight, and she gets out of bed to respect his request for momentary solitude. This fleeting acknowledgment of the come-here-go-away dynamic, the paradoxical component of most romantic relationships, serves as the film's most insightful look at attachment at any cost. The rest is much like the donuts that Violet uses as a key prop in a research experiment: stale and not good for you.