American Idol is one of the most successful reality TV shows of all time. Fans love to see the contestants of the series finally have all their dreams come true by revealing their vocal abilities to a worldwide audience. We also secretly love to re-watch all of the "bad auditions" because of the look on Simon Cowell's face as he tries to contain his laughter.

RELATED: 15 Crazy Rules That Reality TV Stars Have To Follow

The series has seen many panels of judges come and go, but for true fans of the series, Simon, Paula, and Randy will always be the icons of Idol who have made it a truly memorable show. Since the beginning, we have seen a wide variety of talented vocalists, yet sometimes we find ourselves shocked by the fact that they don't end up winning the competition. Here are some of those unfortunate contestants.

KATHARINE MCPHEE

katharine mcphee

Katharine Mcphee was a fan favorite on American Idol, and viewers were shocked when the pop/R&B singer lost to Taylor Hicks in Season 5. While Hicks has pretty much been MIA since his win on the popular singing competition show, Mcphee refused to shy away from the spotlight.

RELATED: American Idol: The 5 Most (& 5 Least) Deserving Champions of All Time

Since her 2006 run, she has gone on to release several hits and has even committed herself to an acting career starring in movies and TV shows such as The House Bunny and Smash.  Fans of the talented vocalist claimed to have a case of "Mcpheever" and would go on to follow her success long after Idol.

DAVID ARCHULETA

David Archuleta was a beloved contestant on American Idol who was only 16 during his run on the singing competition program (which means he was still studying in school while competing on the show).  That means in the morning he was studying the periodic table while at night he was performing in front of millions. Talk about living a double life!

He ended up in second place, losing to that year's winner, David Cook. Not too shabby for a 16-year-old, huh? Archuleta went on to release several hit singles, most notably his song "Crush," which peaked at #2 on the Billboard Hot 100 Charts in 2008.

CLAY AIKEN

American Idol fans were drawn to Clay Aiken since the second season of the program, where he came in second place. Aiken lost to Ruben Studdard, yet although he ended up being the runner up, he still went on to become the fourth best-selling Idol artist during the course of the entire show, which is still running today.

He has received so much love and praise since his days on the competition, gaining the vote as the "Favorite American Idol Contestant" for People Magazine back in 2006. He was also awarded "the most loved reality TV-star of all time" by TV Guide in 2005. Not bad, Clay!

JENNIFER HUDSON

When Hudson sang the words "and I am telling you, I'm not going", she meant it! Although Jennifer Hudson only received the position of seventh place on Season 3 of American Idol  (which we're still utterly confused about), she went on to become one of the most successful former contestants of all time.

RELATED: American Idol: 25 Rules Every Contestant Needs To Follow

Seriously. What other Idol contestant could say they got to star alongside Beyonce in the hit movie Dreamgirls? Hudson has continued to keep herself busy in the spotlight by taking top-notch roles in films such as Sex and the City: The Movie and The Secret Life of Bees. She has worked as a judge for the UK's The Voice and will go on to star in the film version of Cats The Musical. 

HALEY REINHART

Haley Reinhart was praised on American Idol for her raspy yodeling voice, and years later we are still listening to her incredible cover of Elton John's "Benny and the Jets" on repeat. In 2018, she worked with the one and only Jeff Goldblum on his jazz album, The Capitol Studios Sessions, singing alongside the Jurassic Park actor.

RELATED: F Is For Family Voice Cast & Character Guide

She is also adored for her vocal work in the band Post Modern Jukebox, which is known for covering jazzy renditions of famous pop songs. In 2017, Reinhart began her voice-acting debut on Netflix's F is for Family, an animated comedy created by well-known comedian Bill Burr.

ADAM LAMBERT

Adam Lambert perofrming with Brian May

It's crazy to think the current lead vocalist of Queen lost on American Idol, taking second place to Season 8's winner, Kris Allen. There were no hard feelings though because Allen and Lambert formed an extremely close friendship during their time on Idol, where they even roomed together.

RELATED: 10 Fakest Current Reality TV Shows (And 10 That Are Surprisingly Real)

Perhaps one of the most successful American Idol contestants in the history of the reality show, Lambert has since gone on to fill some big shoes, stepping in for Freddie Mercury as the lead singer in one of the most popular and successful rock bands of all time, Queen. He has also taken a role in the hit series Glee, and most recently, he performed at The Oscars 2019.

CHRIS DAUGHTRY

During Season 5 of American Idol, Chris Daughtry took fourth place, losing that year to Taylor Hicks. He has since gone on to find major success by forming his own band, Daughtry, where he has created several smash hits.

These tracks include "It's not over" which received a nomination at The Grammy's for best rock song, "Waiting for Superman", and "Home". He currently holds the position as the third best-selling American Idol contestant, with Kelly Clarkson and Carrie Underwood ahead of him.

ELLIOT YAMIN

Elliot Yamin was praised for his soulful and raspy voice on American Idol Season 5, where he took third place. In 2007, his album Elliot Yamin placed at number four for the Billboard Top 100 chart and his song "Wait for you" was listed on the Top 5 charts on Pop 100 Airplay.

The music video for his famous "Wait for you" single was listed at number one on VH1's Top 20 Countdown. Simon Cowell even claimed Yamin to be the "best male vocalist in Season 5." When you get praise like that from Simon Cowell, you know you're doing alright!

KELLIE PICKLER

Although the blonde-haired beauty only went on to receive sixth place on American Idol Season 5, she managed to build a successful career as a musician after competing in the reality program.

It isn't often that you get to co-write a song with top-selling pop star Taylor Swift, but the Idol contestant did just that for her song "Best Days of Your Life." Although she didn't win this competition, Pickler did go one to take the crown as the winner of Dancing With The Stars Season 16. Now, she hosts a daytime talk show, Pickler and Ben.

MELINDA DOOLITTLE

Melinda Doolittle singing with a band behind her

Her last name may be Doolittle, but she is able to do a whole lot. Vocally, she shines as one of the best contestants to ever walk the American Idol stage, despite the fact that she came in third place during Season 6. Perhaps if it wasn't for her nerves getting the best of her, she would have been the winner for that season.

We fully understand where she's coming from, though, because performing in front of millions (and Simon Cowell) is no walk in the park! Some of her best covers on the show include "My Funny Valentine" by Frank Sinatra, and "Since You've Been Gone" by Idol alum Kelly Clarkson.

NEXT: 15 Behind-The-Scenes Reality TV Photos We Can't Unsee