U2 frontman Bono has sleepless nights before concerts because he gets terrified he will let fans down by failing to hit his high notes. The Vertigo hitmaker is highly critical of his own performances and also worries he will damage his voice if he doesn't deliver the high notes in the right way. The 46-year-old says, "The morning before a show I get nervous. I can wake up in the middle of the night with a sick feeling. "I have to hit very high notes and if you hit them wrong you can put your throat out. So there's a 'Will I? Won't I?' aspect to it. "That sense of, 'How could I meet the levels of anticipation?' If you are a rock star and need 25,000 people telling you they love you, obviously you must be a very insecure person."