Transpose the communal exuberance of Los Campesinos! to the U.S. and you’ve got this quintet, who prove that sunny, adolescent, pop-rock catchiness will never go out of style. For all its youthful pathos, though, Never Trust a Happy Song evokes pop colors bright enough to glow at tempos just short of manic — even “Slow” doesn’t stay that way for long. “Naked Kids” describes a skinny-dipping outing in a flirtatious call-and-response between Christian Zucconi’s enthusiastic yelp and Hannah Hooper’s indie-girl aloofness: “Here’s to livin’ out our dreams,” toasts Zucconi. Youth must be served, after all.