IF YOU OVERLOOK their pallor, theater kids have a youthful glow, probably because a lot of their time is spent playing make-believe and doing improv exercises. Comedy improvisers are next-level stage dweebs who are practically nuclear with that rosy-cheeked exuberance, what with all the riffing and saying yes. But what happens when those theater kids get old? That’s the premise of comedian Mike Birbiglia’s latest, Don’t Think Twice.

Actually, it’s a whole lot sweeter than just watching decrepit comedy improvisers stumble around onstage: These thirtysomethings are just a little too long in the tooth for their improv group, the Commune, and their modestly attended shows. Troupe leader Miles (Birbiglia) teaches improv classes and sleeps with his students, while his band of onstage besties includes struggling comedians like under-achieving Sam (Community’s Gillian Jacobs, wonderful as usual) and graphic novelist Allison (Garfunkel and Oates’ Kate Micucci). But it’s Jack (Keegan-Michael Key of Key & Peele) who becomes the group’s breakout star.

Jack’s overnight success upends the Commune, sending the tight-knit group off the deep end as they reassess their careers, their futures, and their simmering resentment. What makes Don’t Think Twice such a smart, universal comedy is the core friendship of the group: You can feel the genuine waves of affection coming off Birbiglia & Co. They’ve got each other’s backs, even as their relationships start to go sideways. It’s beyond refreshing to see a comedy where friends aren’t pitted against each other to manufacture conflict. This is an oh-so-relatable film that shows how hard it is to watch a friend succeed where you have failed, and how tricky it is to reconcile pride and jealousy. Don’t Think Twice is like that difficult life lesson—only a lot funnier, and way more charming.