If you often find yourself quoting famous figures - who also seem to have more quotes attributed to them than time to speak the words - then you may be more wrong than you are erudite or smart. I'm certainly guilty of this psuedo-intellectual misattribution, but I'm not the only one, apparently. At least according to Good.is, it happens all the time:
That Mark Twain was something else, wasn’t he? He said so many memorable things, like “If you don’t like the weather in New England, just wait a few minutes” and “Golf is a good walk spoiled.” What a writer, what a guy.
Unfortunately—even though Twain is the great American humorist—he didn’t say either of those things. Twain is what scholar Fred Shapiro calls a “quote magnet,” someone who receives credit for sayings and proverbs that never passed their lips or pens. Also called “Churchillian drift” by Nigel Rees, quote magnetism is a common phenomenon that infects everything from student papers to political speeches, and respected books of quotations aren’t immune. As quote experts Rees and Shapiro have shown, “So-and-so said” are some of the least trustworthy words in the language.
The article goes on to talk about reasons for this particular brand of passive intellectual laziness, and the common ingredient seems to be, well, commonness. According to the article, "In America, Shapiro said that “people associated with folksiness” such as Twain, Benjamin Franklin, Abraham Lincoln, and Yogi Berra are the big quote magnets."