Mona Lisa Principle
The notion that while there isn't necessarily something wrong with someone/something, the two elements aren't a match.
"Dude, why did y'all break up?"
"Classic Mona Lisa Principle. She was beautiful, mysterious, and intriguing, but (pointing to my brain) didn't match a damn thing in my house."
"Classic Mona Lisa Principle. She was beautiful, mysterious, and intriguing, but (pointing to my brain) didn't match a damn thing in my house."