The insult-swordfight in monkey island 1 is hillarious!
Some Quotes from the Monkey Island series:
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Swordsman: You fight like a dairy farmer.
Guybrush Threepwood: How appropriate, you fight like a cow.
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Cabana Boy: Let me see your membership card and I'll let you through!
Guybrush: You don't need to see my identification.
Cabana Boy: I don't need to see your identification.
Guybrush: I'm not the pirate you're looking for.
Cabana Boy: You're not the pirate I'm looking for.
Guybrush: I can go about my business.
Cabana Boy: You can go about your business.
Guybrush: Move along.
Cabana Boy: Move along, move along... hey! Your mind tricks won't work on me, boy!
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Guybrush: What's your name?
Slappy Cromwell: Cromwell, Slappy Cromwell. It's not my real name actually. My agent told me my given name just didn't have star quality.
Guybrush: What was your given name?
Slappy Cromwell: Rex Fortune, Adventure Seeker.
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Edward Van Helgen: What! You shot my banjo!
Guybrush Threepwood: You can't be sure of that. That shot may have come from the grassy knoll.
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Elaine Marley: You know... I don't think my father would approve of me dating the undead, and you're probably too nice a zombie-pirate for me anyway. Let's just be friends instead.
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Guybrush Threepwood: How can you see without eyeballs?
Murray: How can you walk around without a brain? Some things no one can answer.