Jack Kerouac said this quote

And this is not the happiness of a magazine writer who sends in his gay little philosophy of life to the editor for the one paragraph spread in front of the magazine: This is a serious happiness full of doubts and strengths. I wonder if happiness is possible. It is a state of mind, but I'd hate to be a bore all my life, if only because of those I love around me. Happiness can change into unhappiness just for the sake of change.