U2, ‘No Line on the Horizon’: Aidin Vaziri | Watching U2 rehash the stage set and pounding disco beats of the “Zooropa” era at the Grammys was a bad sign: Could one of the world’s best rock bands be so devoid of ideas that it has to return to its second- or third-worst album for inspiration? You probably don’t want to know the answer. The backward-looking “Get on Your Boots,” a single that is as clunky as its title, isn’t the biggest slip to be found on “No Line on the Horizon.” In fact, it’s one of the few songs that actually has a pulse on a record bogged down by long, droning ballads and groaning electro-rockers that would have sounded dated even when the Prodigy ruled the charts. “Moment of Surrender,” “Stand Up Comedy,” “Breathe” – at best, these songs should have been “Pop” B-sides. Bono’s lyrics, meanwhile – usually driven by life’s big, existential questions – suffer a major lapse as well. At one point on “Unknown Caller,” the band members sing in unison, “Force quit and move to trash!” If that doesn’t indicate that they made this album while the Edge was tooling around on Facebook, what does? Later, on “I’ll Go Crazy If I Don’t Go Crazy Tonight,” Bono lends one of his traffic-stopping wails to the line, “There’s a part of me in the chaos that’s quiet/ And there’s a part of you that wants me to riot.” Even Lenny Kravitz would have thought that couplet too lazy for public consumption. “No Line on the Horizon” is rife with so many embarrassing moments that not even Brian Eno and Daniel Lanois – the same production team behind U2 classics “The Unforgettable Fire,” “The Joshua Tree” and “Achtung Baby” – can save it from circling the drain before it’s over.