"Rick Rubin has a larger looming presence on this album than his 'thank you' deserves. He asked 'Why can't more people cover U2 songs?' And it's because, with all the great sounds and arrangements, you can forget that there isn't a song there."
- Bono on Rubin's influence on Songs of Innocence
Bono is almost always seen wearing sunglasses because of an allergy to salicyclates and adverse reaction to light.