The trouble with most people is that they quit before they start.
Two per cent. is genius, and ninety-eight per cent. is hard work.
Every wrong attempt discarded is another step forward
I know of over 3,000 ways [that] a light bulb does not work.
I can never pick up a thing without wishing to improve it.
There seems to be no limit to which some men will go to avoid the labor of thinking. Thinking is hard work.