If a mid-life crisis happens in one’s fifties, what is a crisis in your thirties called? Perhaps it’s just permanent adolescence. “ Adult Best Friends ” mines its comedy from the friction caused when one of a pair of best friends moves into adulthood and gets married, while the other remains stuck. Doing double duty as the film’s screenwriters and stars, Katie Corwin and Delaney Buffett craft a believable friendship for their lead characters (also called Katie and Delaney) and write some decent dialogue about why people would or would not marry.
Something is missing, however — the film ends up being more dull than hilarious. Katie and Delaney have been friends since they met at a sleepover in their pre-teens. When Katie’s sweet boyfriend John (Mason Gooding) proposes, she finds it hard to tell her pal.
Delaney — who hasn’t ever liked any of Katie’s boyfriends — parties hard, sleeps with whomever she pleases, and has no plans to grow up or settle down. So when Katie invites her on a BFFs-only weekend jaunt to their childhood beach town to break the news, complications ensue. Chance encounters from their past happen, of course.
Bizarre strangers meddle in their affairs, of course. Katie and Delaney break up and then make up. Of course.
“Adult Best Friend” tries for humor at all times, its comedy ranging from cringe to heartfelt to smart and back again. A throwaway joke referencing “Benedict Arnold” lands well. A more protracted one about dog excrem.