Factual error: In season two the show makes Dalton look like it's in a suburb of Lima. Dalton Academy is suppose to be located in Westerville, OH, which is two hours southeast of Lima. Kurt & Blaine would not be able to go to the "Lima Bean" coffee shop every day if this was the case.
Continuity mistake: During "Blame It on the Alcohol", when Quinn is shouting at Puck, her hair is messy and straight. Yet a little while after, during "Don't You Want Me", her hair is curly and styled perfectly.
Audio problem: During the beginning of Rachel's "Baby One More Time" fantasy, the tapping sounds and her pencil's movements don't match up.
Continuity mistake: During "Grilled Cheesus", the grilled cheese sandwich with the face of Jesus changes occasionally between shots. Sometimes the burn is slightly darker, or the edge is changed.
Revealing mistake: Season 2, episode 4 (Duets): When Brittany lifts Artie from his chair and carries him to her bed, right before she puts him down, he is obviously lifting his feet to prevent them from bumping into the bedframe.
The Rocky Horror Glee Show - S2-E5
Continuity mistake: When the kids are practising the 'Dammit Janet' song, Finn draws a heart on the whiteboard in the back of the choir room. The shape of the heart changes with almost every shot it is in.
Continuity mistake: During "Never Been Kissed", just after Sue activates the confetti cannons and is talking to Will, the amount of confetti on Will's shoulders changes between shots.
Continuity mistake: During season 2 "Never Been Kissed", just as the Warblers begin to sing "Teenage Dream", a boy with a briefcase walks in front of Kurt, heading towards the left. Two shots later, the same boy with the breifcase walks left in front of him again.
Continuity mistake: While the Warblers are singing "Teenage Dream", during the closeups of Kurt, his bag's strap is under his jacket's lapel, but in the long shots, it's on top of the lapel.
Continuity mistake: Puck butters the floor, and as Kurt slips and falls, The Substitute is not where she had been standing. The next shot, she's still there. (00:07:45)
Continuity mistake: In the "Singing In the Rain" dance, the second time the three guys are on their knees, they splash water with their hands. The third time they splash, the water drops are moving toward the stage instead of away. And the rain in the background is falling up.
Continuity mistake: When Sue and her mother are singing "Ohio", during the closeups, Sue has her arm around her mother's waist, yet in the wide shots, Sue's arm is hanging by her side.
Audio problem: During "Marry You", in the wide shots where Carole is coming down the aisle and the Glee kids are in the background, the lyrics and their mouth movements don't match up.
Visible crew/equipment: During "Valerie", as Santana resumes singing right after Mike has somersaulted over Brittany, you can see a cameraman filming the girls' group in the bottom left corner of the screen. (00:32:15)
Continuity mistake: During Season 2, Episode 9 (Special Education), just as Blaine is singing "Hey soul sister, I don't wanna miss." for the last time, he is several feet in front of the other Warblers. But during the next shot, as he is singing ".a single thing you do.", he's right in front of them. So he jumped back several feet between two shots.
The Sue Sylvester Shuffle - S2-E11
Continuity mistake: When the Warblers are singing "Bills, Bills, Bills", one of them throws the sheets of music up in the air as he spins. For the remainder of the song, the sheets are on the floor during some shots, but have disappeared in others.
Audio problem: In "Silly Love Songs" during the final song You can hear Blaine singing "I can explain." but in a couple of the shots he is lip-syncing to the "I love you". Next shot is he is back to singing his solo part.
Continuity mistake: When Lauren drags Puck into the storage closet for Seven Minutes In Heaven, there are hearts on the wall which appear to be decorations for Valentine's Day. As the Seven Minutes In Heaven happened prior to Sectionals, which was well before Valentine's Day, these shouldn't be there.
Continuity mistake: During Mike's "Bubble Toes" dance number, the chain on his pocket watch switches between being over a foot long, swinging about as he dances, and being only a few inches long. (00:25:40)
Answer: The show is purposefully stylized and over the top. It is not designed to be an accurate, realistic representation of American high school. The idea that the glee club is so unpopular other students can literally throw garbage at them with impunity is an over-exaggeration of how glee club is considered "un-cool" compared to things like football. However, there is a second way of looking at it. The audience is simply never shown anyone getting into any trouble for throwing slushies. Just because we don't see it doesn't mean it never happened.
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