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That feeling you get when you've had too much coffee in the morning and it's starting to wear off. Its stimulative effects don't always wear off evenly, leaving you feeling jittery AND exhausted. Food and water help; fortunately the most common time for a caffeine downer is right before lunch.
"Anyone want a second cup of coffee?"

"I'm tempted, but I'll get a caffeine downer in an hour for sure."
by Trinadtsat Tomitsu August 24, 2007
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