Troubles are only mental; it is the mind that manufactures them, and the mind can gorge them, banish them, abolish them

It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so.

It was just my willpower, my determination. I had to wait a long time,

What's the use you learning to do right, when it's troublesome to do right and ain't no trouble to do wrong, and the wages is just the same?

I, Mark Twain being of sound mind, have spent everything

The trouble ain't that there is too many fools, but that the lightning ain't distributed right.