World Smile Day (celebrated on the first Friday in October) was founded to honor Harvey Ball, the commercial artist who created the iconic yellow smiley face image in the 1960s. It's no wonder that the happy image took off—humans have evolved to be attracted to smiles. So it's also no wonder that we sing about their charms as well. Here are the stories behind seven smiley songs, from upbeat crooners to cheesy power ballads.

1. "SARA SMILE" // HALL & OATES

In 1975, "Sara Smile" was Hall & Oates's breakthrough single—their first to hit the Top 10—and its namesake influenced countless other songs by the duo. Daryl Hall's longtime girlfriend, Sara Allen (they were together for 30-some years), would later help pen many of their hits, like "You Make My Dreams," "Private Eyes," and "Maneater." But for this sweet ballad, Hall later said that it was a sincere appreciation about "the essence of a relationship … It's a heartfelt story. It's the real thing."

2. "A WINK AND A SMILE" // HARRY CONNICK, JR.

The easy swing of "A Wink and a Smile" may sound like an old jazz classic, but it was written specifically for the Sleepless in Seattle (1993) soundtrack by composer Marc Shaiman and lyricist Ramsey McLean. Shaiman and director Rob Reiner were big fans of Harry Connick, Jr.—he'd been scouted to do the entire soundtrack for When Harry Met Sally… four years prior; that album was hugely successful and won Connick his first Grammy—so when they needed a jazz pianist for a key song for Sleepless, they knew where to turn. "Wink" was nominated for Best Original Song at that year's Oscars but lost to Bruce Springsteen's "Streets of Philadelphia."

3. "YOUR SMILING FACE" // JAMES TAYLOR

It's been speculated that this sunny song was written about his then-wife Carly Simon, but according to a 2009 biography on Taylor, the song was about their young daughter, Sally. Imagining the "pretty little pout" of a toddler turning a proud dad "inside out" might just push this saccharine song into unbearable cuteness territory.

4. "YOU'RE NEVER FULLY DRESSED WITHOUT A SMILE" // ANNIE

Written by Charles Strouse and Martin Charnin for the 1977 Broadway musical Annie, "You're Never Fully Dressed Without a Smile" opened the second act with an upbeat Depression-era radio song meant to cheer the downtrodden public. For the 2014 remake of the movie starring Quvenzhané Wallis, Sia released a cover for the soundtrack that upgraded some of the more dated fashion references (like replacing "Chanel, Gucci" for "Beau Brummell-y") and made it an empowerment anthem as opposed to a 1930s radio jingle.

5. "SHE SMILED SWEETLY" // THE ROLLING STONES

"Here, Mick Jagger significantly tones down his approach to women," the tome The Rolling Stones: All the Songs declares. "There is no misogynistic double meaning." However, misogyny (or lack thereof) aside, it's still unclear who—if anyone—this ballad was about. In 1968, the year after "She Smiled Sweetly" was released, Jagger told Rolling Stone that their numerous songs centered on women were about "Different girls. They are all very unthoughtout songs." And though many, including music biographer Stephen Davis, pointed to Jagger's late-'60s relationship with singer Marianne Faithfull as being the muse for "the first real love lyric Mick wrote," Jagger later told NME that the song was meant to have religious connotations. "It was he smiled sweetly, but someone changed it," he said.

6. "WHEN YOU'RE SMILING (THE WHOLE WORLD SMILES WITH YOU)" // VARIOUS

This American standard was written in 1928 by the trio of Shay, Fisher, and Goodwin and released that year by Seger Ellis, a jazz musician from Texas. Ellis's early recording included an intro verse ("I saw a blind man/he was a kind man/helping a fellow along // One could not see/one could not walk/but both were humming this song") that was cut from the popular subsequent versions by people like Dean Martin, Louis Armstrong, Billie Holiday, and Frank Sinatra.

7. "WHEN I SEE YOU SMILE" // BAD ENGLISH

In the late '80s, a supergroup of Babys and Journey musicians teamed up behind lead singer John Waite to form Bad English, a band SPIN once called "music for the masses who like their rock 'n' roll lite." Waite and company (including longtime Journey guitarist Neal Schon) started putting together their eponymous first album, and according to Waite, the band was opposed to doing any outside songs. Their label had sent them a Diane Warren power ballad though, and Waite insisted on using it; "When I See You Smile" is one of only two songs on the album that Waite doesn't have a writing credit on. He recorded the vocals in two takes, and the song hit No. 1 for two weeks in November 1989.