Twain should need no introduction for Western visitors, being a giant in American literature and the English language. Not only is his mastery of language admirable, but also how he lived his life: Besides tackling the sin of slavery with immortal novels, he publicly opposed racism and imperialism, and took honor seriously - including in a failed business venture worth about $8 million (adjusted dollars) where he repaid his debts despite no legal obligation to do so.
The list below was compiled primarily from Wikiquotes and the Twain House; the latter is a must-visit should you find yourself near Hartford, CT (frankly, there won't be much else to see/do in the area).
"Be respectful to your superiors, if you have any."
"Most writers regard truth as their most valuable possession, and therefore are most economical in its use."
"Always acknowledge a fault frankly. This will throw those in authority off their guard and give you opportunity to commit more."
"Humor must not professedly teach, and it must not professedly preach, but it must do both if it would live forever. By forever, I mean thirty years."
"Travel is fatal to prejudice, bigotry, and narrow-mindedness, and many of our people need it sorely on these accounts."
"None but the dead have free speech."
"Whenever you find that you are on the side of the majority, it is time to reform."
"Never let your schooling interfere with your education."
"I was born modest, but it didn't last."
"I have been complimented many times and they always embarrass me; I always feel that they have not said enough."
"I was sorry to have my name mentioned as one of the great authors, because they have a sad habit of dying off. Chaucer is dead, Spencer is dead, so is Milton, so is Shakespeare, and I’m not feeling so well myself."
"I am an old man and have known a great many troubles, but most of them never happened."
"Thousands of geniuses live and die undiscovered — either by themselves or by others."
"You can't depend on your eyes when your imagination is out of focus."
"Many a small thing has been made large by the right kind of advertising."
"Familiarity breeds contempt — and children."
"There is no sadder thing than a young pessimist, except an old optimist."
"All good things arrive unto them that wait – and don't die in the meantime."
"To eat is human . . . to digest, divine."
"Always do right. This will gratify some people, and astonish the rest."
"If you tell the truth you don't have to remember anything."
"Get your facts first, and then you can distort them as much as you please."
"The lack of money is the root of all evil."
"Never tell the truth to people who are not worthy of it."
"Prosperity is the best protector of principle."
"Man is the only animal that blushes. Or needs to."
"He had discovered a great law of human action, without knowing it — namely, that in order to make a man or a boy covet a thing, it is only necessary to make the thing difficult to obtain."
"He had only one vanity; he thought he could give advice better than any other person."
"To create man was a fine and original idea; but to add the sheep was a tautology."
"He is a stranger to me, but he is a most remarkable man — and I am the other one. Between us, we cover all knowledge; he knows all that can be known, and I know the rest."
"Tomorrow night I appear for the first time before a Boston audience — 4000 critics."
"I have no race prejudices nor caste prejudices nor creed prejudices. All I care to know is that a man is a human being, and that is enough for me; he can't be any worse."
"He [George Washington] was ignorant of the commonest accomplishments of youth. He could not even lie."
"A man is never more truthful than when he acknowledges himself a liar."
"They spell it "Vinci" and pronounce it "Vinchy". Foreigners always spell better than they pronounce."
"H'aint we got all the fools in town on our side? And ain't that a big enough majority in any town?"
"Clothes make the man. Naked people have little or no influence on society."
"Reader, suppose you were an idiot. And suppose you were a member of Congress. But I repeat myself."
"In religion and politics, people's beliefs and convictions are in almost every case gotten at second-hand, and without examination, from authorities who have not themselves examined the questions at issue, but have taken them at second-hand from other non-examiners, whose opinions about them were not worth a brass farthing."
"The easy confidence with which I know another man's religion is folly teaches me to suspect that my own is also."
"The minister gave out his text and droned along monotonously through an argument that was so prosy that many a head by and by began to nod — and yet it was an argument that dealt in limitless fire and brimstone and thinned the predestined elect down to a company so small as to be hardly worth the saving."
"I have no special regard for Satan; but, I can at least claim that I have no prejudice against him. It may even be that I lean a little his way, on account of his not having a fair show. All religions issue bibles against him, and say the most injurious things about him, but we never hear his side. We have none but the evidence for the prosecution, and yet we have rendered the verdict. To my mind, this is irregular. It is un-English, it is un-American; it is French."