A man visits the doctor for a checkup, and after some tests, the doctor comes in with a grave look on his face.

Doctor: Well, I have some bad news and some really bad news.

Man: Well, give me the really bad news first.

Doctor: You have cancer, and only 6 months to live.

Man: And the bad news?

Doctor: You have Alzheimer's disease.

Man: That's great. I was afraid I had cancer!