why are heart attacks funny, when cancer isn't?
It's not hard to find XL burgers w/ names like "double coronary.," but hard to find tobacconists w/ names like "Lung Cancer Shoppe." Having lost a parent apiece to cancer and heart disease, I feel about the same way about each. I welcome your thoughts on the difference.
The Answer:
Because heart attacks are (seemingly) the result of a conscious choice whereas dying of cancer is somewhat random in its effects. A heart attack is funny for the same reason the Darwin Awards are "funny" - you were foolish enough to tempt fate and got what was coming to you.
That being said if there were pictures of people playing in radioactive waste or eating plutonium with a caption that said "this is why you have leukemia" it would be comedy gold.