Between his many spoof-y music videos, creative appearances in Nationwide ads and longstanding CMA Awards hosting gig with Carrie Underwood, Brad Paisley has made a habit out of incorporating comedy into all aspects of his career. But while he may be known for his humor, Paisley says that the most important song of his career was also one of his most straightforward and sincere.

That song is "Letter to Me," a track that Paisley released in 2007, off of his fifth studio album, 5th Gear. The song spent four consecutive weeks at the top of the Billboard Hot Country Songs chart in early 2008, but Paisley admitted in a recent interview that he never expected "Letter to Me" to become a single at all.

"That song was written 100 percent for myself; it was never intended to be a single," Paisley recalled during an event at the 2018 Country Radio Seminar. "We cut it for all the right reasons, which basically were that we knew it needed to exist.

"We sit around in [Nashville] a lot and say, 'Here's a thing we could put together that the fans would want to buy,'" Paisley adds. "But that's the wrong way to do it. We need to think more about what's going to get people emotional. I think that the best music is the music that you mean."

Paisley has said that he was inspired to write "Letter to Me" after his wife, actor Kimberly Williams-Paisley, was asked to contribute to an anthology titled What I Know Now: Letters to My Younger Self, in 2007. The lyrics of the song find an older man giving his younger self advice ("You've got so much up ahead / You'll make new friends / You should see your kids and your wife ... Have no fear / These are nowhere near / The best years of your life"), but it's the details of the song that impress upon the listener how personal and autobiographical "Letter to Me" really is: "First I'd prove it's me by saying / 'Look under your bed / There's a Skoal can and a Playboy,'" Paisley sings in the first verse. "At the stop sign at Tomlinson and 8th / Always stop completely; don't just tap your brakes."

Paisley believes the song resonates with so many fans because of its emotional honesty: "The best place [for art to come from] is from a place of truth," he says. "The reason why you laugh at something is because there's an element of truth, something you recognize in it. A lot of the best country music is about exactly that."

See Brad Paisley's Childhood Photo