An expression of surprise, emphasis, exasperation, outrage, and so forth. These all are euphemisms for “for God’s sake,” which in some circles is considered blasphemous. “For heaven’s sake” dates at least from the nineteenth century. “For Pete’s sake” appeared in Dialect Notes in 1924. “For pity’s sake” dates from the sixteenth century; Michael Drayton used it in one of his Idea sonnets of 1593: “Rebate thy spleen, if but for pities sake!” See also for the love of Mike/Pete/God.