A situation in which two or more parties believe to have a mutual understanding of the subject matter, but unknowingly are addressing two independent thoughts or conclusions.
Direct from Three's Company:

Mr. Furley is suffering from Jack Tripper Syndrome and is standing outside the bathroom and eavesdropping while Jack and Chrissy are installing a shower curtain.

Jack Tripper: Okay, Chrissy, I'll get in the tub with you, then we can get it on.
Chrissy: Get next to me, I'll show you what to do.
Jack Tripper: This isn't exactly the first time I've ever done this.
Chrissy: Maybe so, but girls are better at this than boys.
Jack Tripper: Come on, Chrissy. A little less talk and a little more action, okay?
Chrissy: Okay, you do your part and I'll do mine. I don't think it'll reach!
Jack Tripper: Of course not, you've got to unfold it first!
by Andrew Rakaczki October 22, 2007
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