I got into a lively debate with a friend after watching “Michael Jackson’s This Is It,” the new documentary that shows Jackson preparing for what would have been his final tour.

The film features one song I really don’t like — the socially conscious, environmental pop ballad “Earth Song.”

“It’s even worse than ‘We are the World,’ ” I said, in reference to the 1985 charity anthem that raised millions for African famine relief. A good cause, sure, but I have a hard time listening to cloying, ultra-sincere lyrics like “We are the world/ We are the children/ We are the ones who make a brighter day/ So let’s start giving,” without feeling embarrassed.

But my friend objected to this characterization. She loved “We Are the World” when she was a child, and she still loves it today. She sent me an e-mail explaining why.

“‘We Are the World’ was a collaboration with so many famous people,” she wrote. “You have to remember the video with all those famous people acting like the rest of us and singing in mics together! There was an educational campaign that went with the song. . . . This wasn’t a song. It was a movement! . . .. Plus, I am a sucker for nostalgia. You shouldn’t fault a seven-year-old for buying into the hype. That was the spring my parents finished a living room addition on our house. The room was empty while they chose furniture and I remember spending hours playing the record over and over and dancing around the room in my tutu.”

As soon as my friend used the Nostalgia Defense, I found it tougher to judge her, or even criticize her musical taste, because everyone I know is totally nostalgic for the movies, books, music and TV shows of their childhood, and has developed elaborate theories to explain why this stuff is really great, despite all evidence to the contrary. Only nostalgia can explain why my sister loves watching the cheesy high school sitcom “Saved by the Bell,” and why my friend Dave was interested in seeing the reportedly terrible film “G.I. Joe” and why I still really like Billy Joel. And if my friend really, truly loved “We Are the World” when she was a kid, well, who am I to argue?

I loved Billy Joel when I was a kid. I played his songs on the piano. “Uptown Girl” was my favorite song. It wasn’t until college that I realized that people who are really into music think Billy Joel’s pretty lame. I popped in a Billy Joel casette during a road trip, and my friend Geoff popped it out after “Pressure,” a synthesizer-driven song from 1982 about the stress of daily life.

“I can’t take any more,” Geoff said, angrily. “He pretends to be this soulful, piano-playing troubadour, but he’s really just this whining, phony millionaire rock star.” I could see what Geoff was getting at — “Pressure” was kind of annoying. So were “Scenes From an Italian Restaurant,” and “Big Shot.”

But I still loved Billy Joel. I couldn’t help it. I felt silly about this love — how could I be such a big fan of such mediocre music? — until I stumbled across a 2002 New York Times Magazine piece about Joel by pop culture/music writer Chuck Klosterman, an unabashed Billy Joel fan who devotes a chapter of his 2003 book “Sex, Drugs and Cocoa Puffs: A Low Culture Manifesto” to his fanhood. I’d long struggled to defend my affection for Joel, and also to understand the widespread derision for him, and Klosterman’s essay provided me with what I’d been looking for: a theoretical framework for talking about Billy Joel.

According to Klosterman, the reasons for the derision are hard to pin down, but likely stem from his total lack of coolness. “The problem is that Joel never seemed cool, even among the people who like him,” Klosterman wrote. “He’s not cool in the conventional sense (like James Dean) or in the self-destructive sense (like Keith Richards), nor is he cool in the kitschy, campy, ‘he’s so uncool he’s cool’ way (like Neil Diamond). He has no intrinsic coolness, and he has no extrinsic coolness. If cool were a color, it would be black — and Joel would be kind of a burnt orange. The bottom line is that it’s never cool to look like you’re trying . . . and Joel tries really, really hard.”

Klosterman then suggests that Joel is masterful at capturing a certain type of loneliness in his music, and writes that the Joel song he most relates to is “Where’s the Orchestra?”, which he calls “one of the loneliest songs in Joel’s entire lonely ouevre.”

I wouldn’t say I relate to “Where’s the Orchestra?”, but I do relate to the loneliness and heartbreak and doom in much of Joel’s music. I also relate to a person who is incapable of being cool. You know, the sort of person who would go to summer camp and tell everyone that her favorite musical artist is Billy Joel, even though all of the other kids picked Def Leppard.

Sometimes I show people the Klosterman essay to try to get them to understand my love for Billy Joel. And I tell them about how I used to run around the living room while listening to Joel’s 1983 album “An Innocent Man.” As my “We Are the World”-loving friend might say, you can’t fault an 8-year-old for confusing Joel’s earnest bombast with great music. Although I’d argue that there’s some great stuff on that album.

Pop culture isn’t all that important in the scheme of things, but my friends and I spend an inordinate amount of time discussing and dissecting and theorizing about it. Our conversations range from the relatively arcane to the very broad. What is the best rock band of all time? Which Prince song is better — “Little Red Corvette” or “Kiss”? Why is “The Breakfast Club” such a great movie? Is Nirvana better than Pearl Jam?

Of course, many of these questions are, at their essence, an attempt to answer something unanswerable: Why do we like what we like?

At the end of the day, it doesn’t much matter. It isn’t a crime to like “We Are the World” or Billy Joel, and a defense isn’t really necessary. The real answer is often quite simple: I liked it when I was a kid. But since nobody wants to admit they have bad taste, more complex theories abound.

Foss Forward makes a weekly appearance in print, in The Gazette’s Saturday Lifestyles section. You can email Sara at sfoss@dailygazette.net.