Humorist Sam Levenson once observed that "the reason grandparents and grandchildren get along so well is that they have a common enemy," but preppy Atlanta lawyer Jason Kelly (Zac Efron) wouldn't entirely agree with that statement. After all, he's employed at a law firm owned by his father (Dermot Mulroney) and hasn't seen his grandpa Dick (Robert De Niro) in years. But when his family reunites for his grandmother's funeral, a grieving Dick asks Jason to drive him to Florida the next day for a golfing vacation, saying that that's what his grandma would have wanted. Jason reluctantly agrees, even though his passive-aggressive tyrant of a fiancée (Julianne Hough) would rather have him stay behind and help her choose between pistachio- or seafoam-colored napkins for their rehearsal dinner next week. But on the drive down, it quickly becomes apparent that the newly single Dick is itching to cut loose with all of the crazy kids on spring break at Daytona Beach, leaving Jason as his appalled chaperone.
And so it goes for the remainder of the movie: Grandpa does something crude and debauched, buttoned-down Jason makes a pained face and tries to act as the voice of reason, grandpa then razzes Jason for being such a stuffed shirt and drags him kicking and screaming out of his comfort zone. This happens over and over again, until Jason wakes up naked on the beach with a penis swastika drawn on his forehead, having learned a lesson about life, or something. Whatever promise Dirty Grandpa held of being a profane yet intelligent and insightful comedy (like Bad Santa or There's Something About Mary) is quickly lost after an unrelenting and meaningless barrage of rape jokes, drug jokes, child-molestation jokes, masturbation jokes, Jew jokes, racial jokes, gay jokes, lesbian jokes, disability jokes, and one joke that somehow finds a reason to reference Mother Teresa's genitals. De Niro delivers these filthy lines with wit, power, and grace -- he's Robert De Niro! Of course he does! But at this point in his career, why does he have to, or want to?
Bette Davis' final role was in the execrable Wicked Stepmother (1989). The last line on a sagging and alcoholic Veronica Lake's resume was playing a Nazi scientist in the Hitler reanimation Z-movie Flesh Feast (1970). A morphine-addicted Bela Lugosi slunk around someone's backyard behind his cape in Plan 9 From Outer Space (1959). Gene Kelly danced for the last time in Xanadu (1980). Joan Crawford, former queen of MGM, ended her screen career trying to lure the titular monster in Trog (1970) out of a cave by shaking a bunch of carrots and calling, "Here, Trog." Robert De Niro turns 73 this year. He had a prostate-cancer scare a few years ago. After watching Dirty Grandpa, this critic went and checked De Niro's /IMDB page, just to make sure he has another movie already in the can coming out later this year. He does, with great relief. God forbid this should be his final role.