A lot of Achtung Baby, to state the obvious, isn't just about being on the receiving end of heartbreak, but dishing it out. The temptation, the action, the reaction, to be the betrayer, not just the betrayed. "You know the sun can sometimes be eclipsed by the moon, you know I don't see you when she walks in the room". Mysterious Ways, Even Better than the Real Thing, Tryin' to Throw your Arms... Temptation, sex, betrayal. Mostly temptation though, and I think that spun itself into reality through the Zoo tour. Maybe not in some awful way, but certainly in that some of the band members were happy to let themselves go, dance very close to whatever line they previously would have stayed far away from. I think that's definitely the place where Zooropa, and the above lyric, is coming from. If you haven't read "U2 At the End of the World" you should. I don't think it's the hangover though. I think Achtung is all the dark thoughts leading through to about 2am. Then they say "f*ck it", pop the red pill and shoot off into Zooropa where they soak it up and don't really give it second thought. When they wake up, two days later, they're confused and angry and guilty and bitter - coming down - and you get Pop.