If you've ever wondered why Adam Sandler needs $80 million to make Grown Ups 2, you can be sure Michael Rosenbaum has as well. In his writing-directing debut, the journeyman actor has made a crass yet saccharine comedy about an immature dude who earns the affections of a gorgeous, sweet, mysteriously single woman. That genre is, of course, Sandler's bread and butter — and Rosenbaum did it here for a fraction of Sandler's usual oversize budget. Back in the Day is no better or worse than any Happy Madison production, which is to say it's good for a couple of fart jokes and otherwise utterly forgettable. Rosenbaum stars as Jim, a struggling actor from suburban Indiana who returns home for his 20th high school reunion. Morena Baccarin plays the one who got away, the actress's otherworldly loveliness undiminished by her character's pedestrian Gap gear. Harland Williams occupies the Rob Schneider role of the grotesque sideshow buddy. In his one great scene, Williams teaches his young son how to capture flatulence in his hand and release it under an opponent's nose. He's a master of fart kwon do. Back in the Day is plenty unambitious, but it does trump Sandler's work in one regard: It's aware of the dangers of nostalgia. As the drug-dealing burnout and the cheerleader turned single mother of three, respectively, Nick Swardson and Liz Carey share an existential moment amid car coitus when they realize that they peaked in life long ago. It's a small scene, but one that knows recognizability is better for the soul than faux cheer.