I admit to being a quotation collector. It started out innocently enough with the purchase of a copy of "Bartlett's Familiar Quotations," begun in 1855 and revised often to update the quotations. My 2002 copy is the 17th Edition. The bible of toastmasters and speech writers (with or without attribution), Bartlett had a simple goal "to show, to some extent, the obligations our language owes to various authors for numerous phrases and familiar quotations which have become 'household words.'" My goals were simpler yet: to appear more erudite than I am by liberally sprinkling into my writing and speech other people's ideas.
Because I also want to appear current, I also refer to the "Yale Book of Quotations," the dictionary of quotations published in 2006 which focuses on modern American quotations, like those from that noted philosopher Lawrence Peter 'Yogi' Berra: " If you come to a fork in the road, take it" (Y. Berra 1989).
Quotations have become a daily obsession. I subscribe to a free vocabulary newsletter "A Word A Day" published in a daily email from Wordsmith. http://wordsmith.org/awad/ The purpose of the column is to reveal the meaning and origins of words. For me the highlight is the quotation at the end titled "A Thought for Today" which never fails to enchant, educate and illuminate (except for the obscure quotes that frustrate and obfuscate). Although I find that the daily words flit from my memory unless already part of my vocabulary, I copy and cling to the quotes like a miser's hoarde and go back to them time and again for inspiration (and seasoning for my writing or speeches). These quotations tend toward deep thoughts from classical or literary sources.
"Every burned book or house enlightens the world; every suppressed or expunged word reverberates through the earth from side to side." - Ralph Waldo Emerson, writer and philosopher (1803-1882).
"We judge ourselves by what we feel capable of doing, while others judge us by what we have already done." - Henry Wadsworth Longfellow, poet (1807-1882).
"No matter what side of the argument you are on, you always find people on your side that you wish were on the other." - Jascha Heifetz, violinist (1901-1987).
I do the same thing with quotations from a legal email newsletter which typically ends with a pithy quote from such luminaries as Mark Twain, Mae West and, a personal favorite, Will Rogers.
" A fool and his money are soon elected."
"You never know how much a man can't remember until he is called as a witness."
"I am not a member of any organized political party. I am a Democrat." (Will Rogers).
When all else fails there are many, many quote sites on the Internet. http://www.quotegarden.com/humorous.html
"Quotators" (or simply "quoters") live in fear of misquotation or at least of being unmasked for misquotation and thereby shown up for the shallow, unoriginal, derivative thinkers that we suspect we are.
In political pieces Abraham Lincoln seems always to be misquoted by those who want the old rail-splitter in their corner for political arguments. http://www.truthorfiction.com/rumors/l/lincoln-quotes.htm
Shakespeare wins the prize for being misquoted more often than any other author, which is understandable given his status as our greatest writer. Of course, some misquotes are mistakes about the lines Shakespeare actually wrote. http://listverse.com/2008/09/15/top-10-shakespeare-misquotes/ The worst mistakes are those quotes confidently attributed to Shakespeare that were actually written by someone else. http://www.shakespeare-online.com/faq/misquotesfaq.html
Here is a pop quiz: which of these quotes were actually written by Shakespeare (or Edward de Vere, Francis Bacon, William Stanley, Christopher Marlowe, Ben Johnson or whoever you think was the actual author of Shakespeare's plays):
1. "Oh what a tangled web we weave
When first we practice to deceive."
2. "No man is an island."
3. "Come live with me and be my love. "
4. "For you suffer fools gladly, seeing yourself as wise. "
5. "For want of a nail, the shoe was lost."
6. "Music hath charms to soothe the savage breast,
To soften rocks, or bend a knotted oak. "
7. "Heaven has no rage like love to hatred turned,
Nor hell a fury like a woman scorned. "
I will provide the answers in a comment to this piece.