The Happiness Equation (nineteen minutes)

reality
_______ = HAPPINESS
expectations

"Why hadn't he realized this before? Everyone knew that if you divided reality by expectation, you got a happiness quotient. But when you inverted the equation- expectation divided by reality- you didn't get the opposite of happiness. What you got, Lewis realized, was hope. Pure logic: Assuming reality was constant, expectation had to be greater than reality to create optimism.

Lewis stepped back from the blackboard, surveying his handiwork. Someone who was happy would have little need to hope for change. But, conversely, an optimistic person was that way because he wanted to believe in something better than his reality."

I effing love this book.