Record labels used to release an artist’s big hit single on the A side of a record or cassette, with some filler on the other side. Here are some cases in which the “filler” was the song the public liked more.

In the late 1980s and early 1990s, rap was a cultural movement. In 1991, the first rap song to hit #1 in the U.S. was, believe it or not “Ice Ice Baby” by Vanilla Ice. And yet the song was initially the B-side to Vanilla Ice’s rap version of Wild Cherry’s disco hit “Play That Funky Music.” That single hit #4 on the charts, but only because people were buying it to get “Ice Ice Baby.”

KISS is one of the most iconic bands of the ’70s, but they didn’t have a lot of hit singles. They did most of their business selling concert tickets, live albums, and merchandise. Oddly, one of the band’s few hit singles was not the raunchy rock n’ roll it was known for, but “Beth,” a ballad sung by the band’s drummer, Peter Criss. The rest of the makeup-ed monsters of KISS don’t even play on the song. At first the song was the B-side to the hard-rocking “Detroit Rock City.” But radio stations started to play “Beth” more, and the single hit #7.

Gloria Gaynor’s “Substitute” was a 1978 disco version of a little-known Righteous Brothers song. It didn’t thrill disc jockeys—not the ones in radio stations or the ones at discos. But DJs in both venues loved the B-side: an empowering song about moving on after a bad breakup called “I Will Survive.” “Substitute” was a minor hit on the R&B chart, but “I Will Survive” went to #1 on the pop chart and became one of the most famous and enduringly popular disco songs ever.

The Red Hot Chili Peppers were primarily a heavy metal-funk band in the 1990s, and didn’t think much of its mellow song “Soul to Squeeze.” It was used as the B-side of both “Under the Bridge” and “Give it Away,” and allowed it to be used on the soundtrack to the 1993 film Coneheads. Although the movie bombed, the song took off. It became a #1 hit at alternative rock radio, and a #22 pop hit. It’s the band’s most successful single ever.