Insanity is doing the same thing while expecting a different result.

Albert Einstein (1879 – 1955), theoretical physicist

Without promotion, something terrible happens: Nothing!

PT Barnum (1810 – 1891), American showman, entertainer and founder of Barnum & Bailey Circus

[On writing poetry] It starts as inspiration and ends as a crossword puzzle.

John Betjeman (1906-1984), English poet and writer