My predilections aside, it's Megan's generalized malaise that provides a backdrop for director Lynn Shelton's mildly amusing but ultimately negligible comedy.
Fearful of marriage to her devoted but drippy boyfriend (Mark Webber), unsure about a career path, and out of synch with her life-long friends, Megan refuses to be swept away by the felicities surrounding the impending wedding of one of her gal pals (Ellie Kemper).
What's a young woman to do? Pursue a career? Make wedding plans of her own? Fit into the group profile being carved out by friends who (thanks to mobile media) are in constant touch with one another?
Megan's answer is a good one: None of the above.
But Laggies is less an incisive character study than a medium-grade, Seattle-based comedy that's slightly elevated by a couple of its performances, notably from Sam Rockwell (as an attorney and the father of a teen-age daughter) and Chloe Grace Moretz (as that rebellious but ultimately good-hearted adolescent).
Sans her British accent, Knightley does her best to bring a bit of luster to a character who's essentially depressed.
Rather than allowing Laggies to find its own rhythm, Shelton relies on the awkward contrivances of Andrea Seigel's screenplay.
By chance, Megan runs into Moretz's Annika outside a convenience store. Annika implores Megan to buy liquor for her underage buddies. Megan does, one of the many questionable decisions she makes.
In need of a week of evasion from personal pressures, Megan crashes at Anika's house. She makes up a story that convinces Rockwell's Craig to let her stay.
An underused Gretchen Mol shows up as Anika's mother, a woman who left her husband to pursue a career as a lingerie model, thus turning Craig into a single dad.
It doesn't take much insight to guess that Megan, who already has accepted her boyfriend's proposal, is going to fall for glib but lonely Craig.