During the Season 2 Live Semi-Final Performances, while Christina Millian was interviewing the other contestants, Chris Mann and Erin Willet had an extended photobomb session behind her.
Carson Daly's confession in Season 3's Top 4 confessionals, answering the question of "Who from the show would you want to be stranded with on a deserted island?"
Carson Daly: "He's a man, but he's pretty like a woman."
Christina Millian and Terry McDermott's chat about Hobbits, followed by a quick cut to a speechless Carson Daly.
Terry: "Have you got a little Hobbit in you?"
Christina: "Not yet!"
Kris Thomas' blind audition in Season 4. During his performance, the judges wrongly assume that it was a female especially when he sings a Whitney Houston song "Saving All My Love for You". Once he judges turns their chair , the guys were shocked that it was a dude.
Adam: I WISH I TURN KNOWING THAT YOU'RE A DUDE!!!
The best part is that Shakira turns her chair and completely making a straight face, knowing that if the secret's revealed, she'll be in trouble.
Sometimes when the judges have to fight for a contestant during the blind auditions.
Shakira's English to Country Dictionary.
Usher saying that Nashville is a state.
Blake: I can't wait to go home to my home state of Nashville!
Shakira comparing a contestant to Margaret Thatcher.
In the UK version, while Kylie Minogue is working with one of her acts, her chair shifts underneath her, which makes a noise that sounds like she was farting. Without even missing a beat, she merely quirks her eyebrows and says "Sorry".