Flirt blind
Like color blind, this attribute is best described as partially or totally unable to distinguish the difference between flirtation and friendliness.
Steve: "Are you flirt blind? She obveously used several double entendres that eluded to sexual intercourse."
Gerald: "Damn it, I wondered why she looked confused on the way to the candy shop"
Gerald: "Damn it, I wondered why she looked confused on the way to the candy shop"