YSJK = You Should Just Know. YSJK-itis is an infliction that can affect anyone, but it's seen most often in your girlfriend/fiancee/wife. It occurs when she's extremely pissed off at you and acting like a total bitch, but refuses to tell you why, because "you should just know."

The person afflicted is usually oblivious to the fact that the other person is completely unable to apologize or fix anything until they know what the problem is. Symptoms can persist for hours or even days.
Man 1: My girlfriend has just been insufferable lately, but no matter how I ask she refuses to tell me why.
Man 2: Sounds like she's suffering from YSJK-itis.
Man 1: Yeah, totally. I'd like to see women pull that shit with doctors or mechanics.
by klopek007 February 22, 2010
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