I used to occasionally watch and enjoy your show, especially your top ten segment. That is why it is so very distressing to me to realize you may have taken leave of your senses; specifically your sense of humor and your sense of propriety.
To help get you back on track, I’d like to offer a some simple tests you can use to determine if your jokes are actually funny or just in poor taste.
Would you consider telling your joke to your mother or daughter? Or a nun? If not, your joke may not be funny. Proceed to Test 2.
Would you consider telling the same joke about your wife, mother, sister or daughter? If not, there is a good chance that your joke is not funny. If you still have doubts, proceed to Test 3.
Test 3: Ultimate Litmus Test
Would you consider telling the same joke about Michelle Obama? Or about Sasha or Malia Obama? If not, your joke is not only not funny but has very likely passed beyond the bounds of decency. Anyone telling this joke should probably be banned from polite society.
Mr. Letterman, since you seem to be both humor and propriety impaired, I hope you make use of these simple tests when formulating your top ten lists in the future.