It is easy to make plans in this world; even a cat can do it; and when one is out in those remote oceans it is noticeable that a cat's plans and a man's are worth about the same. There is much the same shrinkage in both, in the matter of values.

Love seems the swiftest, but it is the slowest of growths

He had an uncommon fondness for cats. As an old man summering in New Hampshire, Twain even rented kittens from a nearby farm to keep him company until he returned home. "If man could be crossed with the cat," said Twain, "it would improve the man, but it would deteriorate the cat." There's always something about your success that displeases even your best friends.

I believe that our Heavenly Father invented man because he was disappointed in the monkey. I believe that whenever a human being, of even the highest intelligence and culture, delivers an opinion upon a matter apart from his particular and especial line of interest, training and experience, it will always be an opinion of so foolish and so valueless a sort that it can be depended upon to suggest to our Heavenly Father that the human being is another disappointment and that he is no considerable improvement upon the monkey.

...heaven for climate, and hell for society.

It is more trouble to make a maxim than it is to do right.

You cannot have a theory without principles. Principles is another name for prejudices.