Wednesday marks the end of an era. After decades on the air at the Ed Sullivan Theater, David Letterman said good-bye to te CBS' “Late Show.” Here are some of his most memorable quotes. Enjoy your read, courtesy of Brainy Quote and Good Reads:

1. “There's only one requirement of any of us, and that is to be courageous. Because courage, as you might know, defines all other human behavior. And, I believe -- because I've done a little of this myself -- pretending to be courageous is just as good as the real thing.”

2. “I have found that the only thing that does bring you happiness is doing something good for somebody who is incapable of doing it for themselves.”

3. “There is no off position on the genius switch.”

4. “People say New Yorkers can't get along. Not true. I saw two New Yorkers, complete strangers, sharing a cab. One guy took the tires and the radio; the other guy took the engine.”

5. “Don't forget it's daylight saving time. You spring forward, then you fall back. It's like Robert Downey Jr. getting out of bed.”

6. “Anything worth doing is worth overdoing.”

7. “If it weren't for the coffee, I'd have no identifiable personality whatsoever.”

8. “If what you've done is stupid, but it works … then it really isn't all that stupid.”

9. “You have Kim Jong Il, and you have his brother, Menta Lee Il.”

10. “I'm just trying to make a smudge on the collective unconscious.”

11. “USA Today has come out with a new survey -- apparently, three out of every four people make up 75 percent of the population.”

12. "If you didn't believe it before -- and it's easy to understand how you might have been skeptical on this point -- if you didn't believe it before, you can absolutely believe it now: New York City is the greatest city in the world." -- Letterman, after the Sept. 11 attacks.

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