"Dirty Day is a father and son song. 'It's a dirty day', was an expression my dad would use and there is a lot of him in there but it was also influenced by Charles Bukowski, the great American writer and drinker. The song is about a character who has walked out on his family and, years later, meets the son he's abandoned. It's not about my father but I used some of my dad's attitude in it."
When U2 were recording The Joshua Tree Bono didn't make it to Ali's birthday, so Bono wrote the song The Sweetest Thing for her.