xy

Pudd'nhead Wilson's New Calendar, Ch. XLVIII
Following the Equator (1897)
Variant: To get the full value of joy you must have someone to divide it with.

“Civilization is a limitless multiplication of unnecessary necessaries.”

Mark Twain (1835–1910) American author and humorist

“April 1. This is the day upon which we are reminded of what we are on the other three hundred and sixty-four..”

Mark Twain (1835–1910) American author and humorist

Variant: April 1. This is the day upon which we are reminded of what we are on the other three hundred and sixty-four.
Source: Pudd'nhead Wilson and Other Tales

“Familiarity breeds contempt — and children.”

Mark Twain (1835–1910) American author and humorist

Mark Twain's Notebook (1935)

“The older I get, the more clearly I remember things that never happened.”

Mark Twain (1835–1910) American author and humorist

“There are those who scoff at the schoolboy, calling him frivolous and shallow: Yet it was the schoolboy who said "Faith is believing what you know ain't so."”

Mark Twain book Pudd'nhead Wilson

Following the Equator (1897)
Source: Pudd'nhead Wilson's New Calendar, Ch. XII

“It's spring fever. That is what the name of it is. And when you've got it, you want—oh, you don't quite know what it is you do want, but it just fairly makes your heart ache, you want it so!”

Mark Twain (1835–1910) American author and humorist

“Good judgement is the result of experience and experience the result of bad judgement.”

Mark Twain (1835–1910) American author and humorist

“The secret of getting ahead is getting started. The secret of getting started is breaking your complex, overwhelming tasks into small, manageable tasks, and then starting on the first one.”

Mark Twain (1835–1910) American author and humorist

Commonly attributed to Twain in computer contexts and post-2000 inspirational books — the first sentence has also been attributed to Agatha Christie and Sally Berger.
Misattributed

“Let us consider that we are all partially insane. It will explain us to each other; it will unriddle many riddles; it will make clear and simple many things which are involved in haunting and harassing difficulties and obscurities now.”

Mark Twain (1835–1910) American author and humorist

“There isn’t time--so brief is life--for bickerings, apologies, heartburnings, callings to account. There is only time for loving--and but an instant, so to speak, for that.”

Mark Twain (1835–1910) American author and humorist

Letter to Clara Spaulding (20 August 1886)

“The lack of money is the root of all evil.”

Mark Twain (1835–1910) American author and humorist

This appears in Twain's posthumous The Refuge of the Derelicts (1905), but it had already been published by other writers. <br class="br">The earliest citation found in Google Books is a 1872 article by Richard Bowker: "Our Crime Against Crimes" https://books.google.com/books?id=YZgBAAAAYAAJ&pg=PA68&dq=The+lack+of+money+is+the+root+of+all+evil&hl=en&sa=X&ved=0ahUKEwjWi5DE1crLAhUI3mMKHeSdB0YQ6AEIKzAB#v=onepage&q=%22lack%20of%20money%22&f=false, in The Herald of Health, vol. 19 no. 2, New York: Wood & Holbrook, February 1872. The saying is placed within quotation marks, perhaps indicating that it was already well-known. <br class="br">A precursor is found in an article from 1859 https://books.google.com/books?id=gpdEAQAAMAAJ&pg=PA209&dq=The+lack+of+money+is+the+root+of+all+evil&hl=en&sa=X&ved=0ahUKEwjWi5DE1crLAhUI3mMKHeSdB0YQ6AEINTAD#v=onepage&q=%22lack%20of%20gold%22&f=false: It is very well to repeat, parrot-like, the old axiom that “the love of gold is the root of all evil;” but it is very certain that in truth—the lack of gold is the great incentive to crime. <br class="br">Disputed

“Travel is fatal to prejudice, bigotry, and narrow-mindedness.”

Mark Twain (1835–1910) American author and humorist

“Religion was invented when the first con man met the first fool.”

Mark Twain (1835–1910) American author and humorist