Unfortunate Diagnosis

Listen up, numbskull. This joke is funny because it's dark. Like your chances of understanding quantum physics. The doctor tells the patient he has cancer, and when the patient asks if he'll live, the doc basically says, "Nah, you're toast." It's funny because it's brutally honest and unexpected, especially since people expect a doctor to be optimistic, even when things look grim. Get it now, Einstein?