Here's a couple of dozen quotes about looking on the bright side.
“For myself I am an optimist - it does not seem to be much use to be anything else.”
Winston S. Churchill
“Choose to be optimistic, it feels better.” Dalai Lama
“Man often becomes what he believes himself to be. If I keep on saying to myself that I cannot do a certain thing, it is possible that I may end by really becoming incapable of doing it. On the contrary, if I have the belief that I can do it, I shall surely acquire the capacity to do it even if I may not have it at the beginning.” Mahatma Gandhi
“What day is it?” asked Pooh. “It’s today,” squeaked Piglet. “My favourite day,” said Pooh.
A.A. Milne
“I am fundamentally an optimist. Whether that comes from nature or nurture, I cannot say. Part of being optimistic is keeping one's head pointed toward the sun, one's feet moving forward.”
Nelson Mandela
“Perpetual Optimism is a Force Multiplier.” Colin Powell
“Even the darkest night will end and the sun will rise.” Victor Hugo
“We are all in the gutter, but some of us are looking at the stars.” Oscar Wilde
“You'll never find a rainbow if you're looking down.” Charlie Chaplin
“How wonderful it is that nobody need wait a single moment before starting to improve the world.” Anne Frank
“Don't be pushed around by the fears in your mind. Be led by the dreams in your heart.” Roy T. Bennett
“A happy person is not a person in a certain set of circumstances, but rather a person with a certain set of attitudes.” Hugh Downs
“We can complain because rose bushes have thorns, or rejoice because thorns have roses.”
Alphonse Karr
“Optimism is a strategy for making a better future. Because unless you believe that the future can be better, you are unlikely to step up and take responsibility for making it so.” Noam Chomsky
“I like to see the glass as half full, hopefully of jack daniels.” Darynda Jones
“One of the things I learned the hard way was that it doesn't pay to get discouraged. Keeping busy and making optimism a way of life can restore your faith in yourself.” Lucille Ball
“Most of the things worth doing in the world had been declared impossible before they were done.” Louis D. Brandeis
“The world is full of painful stories. Sometimes it seems as though there aren't any other kind and yet I found myself thinking how beautiful that glint of water was through the trees.” Octavia E. Butler
“Few things in the world are more powerful than a positive push - a smile. A word of optimism and hope, a 'you can do it!' when things are tough.” Richard M DeVos