"Sweetest Thing" was written by Bono as an apology to his wife for forgetting her birthday. The song opens with a short piano piece before the rest of the band begins to play. Some of Bono's lyrics have been described as reminiscent of John Lennon. The Edge described it as "a beautiful song... which is pop as it should be—not produced out of existence, but pop produced with a real intimacy and purity", also noting that "It's very new for us." It was re-recorded with some lyrical alterations and released in 1998 as a single in its own right for "The Best of 1980–1990". "Hot Press" editor Niall Stokes stated that this track, along with "Race Against Time", is "an indicator of what U2 might have made instead of "The Joshua Tree"."