"If you don't read the newspaper, you're uninformed. If you do, you're misinformed."
"A classic is a book that is praised by all and read by no one."
"Everybody talks about the weather, but nobody does anything about it!"
"Nothing spoils a good story like the arrival of an eyewitness."
"Travel is detrimental to bigotry, prejudice and narrow mindedness."
"There are three kinds of lies: lies, damned lies and statistics."
"It's easier to fool people than to convince them they have been fooled!" — UPDATE: Apparently never said by Twain?
"A banker is a fellow who lends you his umbrella when the sun is shining, but wants it back the minute it begins to rain."
"If you pick up a starving dog and make him prosperous he will not bite you. This is the principal difference between a dog and man."
"Whenever you find yourself on the side of the majority, it is time to pause and reflect."
"The fact that man knows right from wrong proves his intellectual superiority to other creatures, but the fact that he can do wrong proves his moral inferiority to any creature that cannot."
"I think I can say, and say with pride, that we have some legislatures that bring higher prices than any in the world!"
— Mark Twain
See also: Putting words in Mark Twain's mouth