Remember when the New Directions donned those red t-shirts in Glee Season 1 and made believers out of us all? Yeah, that's the moment we knew we were on to something good.

Kurt and Rachel were the definition of frenemies when Glee started. "Defying Gravity" was the moment we realized Kurt wouldn't play second fiddle to Rachel for long. He threw the sing-off to save his dad, not because he wasn't as good as her.

Eve's Jane Adams Girl's Choir might have stolen this number straight from the New Directions set list, but Mercedes Jones sang it better. Almost as good as J. Hud herself.

Rachel Berry met her mother, Vocal Adrenaline coach Shelby Corcoran, during Glee Season 1, but that was AFTER their duet of "I Dreamed a Dream" from Les Miserables.

After quite a rough start to their relationship (which didn't prove to get any easier in later seasons) Finn declared his love for Rachel just before the Glee stars took the stage to sing "Faithfully." Finchel forever!

Meet BLAINE ANDERSON and the Warblers! From the minute he and his backup singers began "Teenage Dream" fans knew they wanted him to stick around.

Who doesn't love a good "Thriller" cover, complete with accompanying dance sequence? Right? That's why it's on the list.

It was the moment Santana realized she was willing to give it all up for Brittany. "Landslide" thrust Naya Rivera's character into the spotlight and we're forever thankful for that moment.

After nearly two complete seasons, fans began to wonder if we'd ever see an original song on Glee. "Loser Like Me" filled the gap and even got some radio play!

While the fandom longed for couples Finchel and Klaine to be together forever, "For Good" marked the moment when Rachel and Kurt's friendship became the show's central story.

Mike Chang finally got a story of his own when he faced his parents about his love for dancing during Glee Season 3's "Asian F" when the New Directions put on Westside Story.

During part of Glee Season 3, Santana, Mercedes, Brittany, and Sugar formed their own group, the Trouble Tones, under the direction of Shelby Corcoran. The "Rumour Has It / Someone Like You" mashup was the highlight of their program.

It was THE hit song of the moment, and Glee HAD TO cover it. (Fans were seriously begging!) Matt Bomer guest starred as Cooper Anderson, Blaine's older brother, and the two sang Gotye's "Somebody That I Used to Know." This one's on the list because MATT BOMER.

After helping Principal Figgins announce Will Schuester as Teacher of the Year, the New Directions serenaded him with "We Are the Champions," a testament to his tireless efforts to help them all succeed.

At the end of Glee Season 3, Burt Hummel proved, once again, that he really is TV Father of All Eternity by performing "Single Ladies" for his son, Kurt.

Glee Season 4 introduced the world to Glee: The New Class, featuring none other than Marley Rose as the new Rachel, with whom she (sort of) sang "New York State of Mind." The song's meaning to both girls solidifies its place in this lineup.

Remembering the moment they were first smitten with one another, Blaine played a haunting, tearful acoustic rendition of "Teenage Dream" during a visit to New York City to visit Kurt. It was during this episode that Kurt found out Blaine cheated.

In what will probably go down as the BEST Glee performance EVER, "The Scientist" featured the show's four main couples breaking up: Finchel, Klaine, Brittana, and Wemma all split, and so did our hearts.

While the writing for Jake Puckerman was somewhat inconsistent (is he a jerk? is he a good guy? is a jerk who wants to be a good guy?), diehards fell in love with Jake and Marley. Their duet on "A Thousand Years" helped.

Santana Lopez left life in Louisville for the bright lights of New York City and showed up as a legit "Girl on Fire." She crashed Kurt and Rachel's apartment and made a home for herself. Plus we love it any time Naya Rivera's given a chance to shine.

Glee sang the Beatles for the first two episodes of season 5, and most of the tribute centered around Blaine proposing to Kurt.

Glee Season 5 Episode 3, "The Quarterback," dealt with the real life loss of Cory Monteith and his fictional character Finn Hudson. Santana's moving tribute, "If I Die Young," was the perfectly fitting memorial song for the character and the man.

The most moving tribute to Finn Hudson, "Make You Feel My Love," came from his love, Rachel Berry. Lea Michele's performance was also a tribute to Cory Monteith, whom she met and fell in love with while filming Glee.

Adam Lambert, as Elliott "Starchild" Gilbert, joined Kurt's band in Glee Season 5. His was, by far, the best guest starring role of the season, if for no other reason than the flawless way he fit with the theme of the show.

In "Opening Night," Rachel realized her dreams of becoming "the greatest star," or at least a small star on Broadway. Soon, however, she left that dream for the glamour of Hollywood and became a fallen star.