Emma laid into Will on the Glee episode "Bad Reputation." She was harsh, but also very much on-point.
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This doesn't happen often, but it happens on the episode "Bad Reputation:" everyone is laughing at Sue Sylvester.
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Rachel finds her name at the bottom of an embarrassing list on the Glee episode "Bad Reputation." She's always atop our list, however. For anything.
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Molly Shannon comes aboard Glee on the episode "Bad Reputation." She and Sue don't exactly get along well.
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Glee Season 1 Episode 17 Quotes

As soon as I figure out the difference between slander and libel, I'm suing you.

Sue

Student: Hey, Ms. Sylvester, let's get physical.
Sue: Not really my type, but I like that attitude.