This was written by Christian Larsen nearly 100 years ago.   I have it framed on my wall and whenever things start to get to me I read it like a mantra.

THE OPTIMISTS CREED

I PROMISE MYSELF to be so strong that nothing can disturb my peace of mind.

I PROMISE MYSELF to talk health, happiness and prosperity to every person I meet.

I PROMISE MYSELF to make all my friends feel that there is something worthwhile in them.

I PROMISE MYSELF to look at the sunny side of everything and make my optimism come true.

I PROMISE MYSELF to think only of the best, to work only for the best and to expect only the best.

I PROMISE MYSELF to be just as enthusiastic about the success of others as I am about my own.

I PROMISE MYSELF to forget the mistakes of the past and press on to the greater achievements of the future.

I PROMISE MYSELF to wear a cheerful expression at all times and give a smile to every living creature  meet.

I PROMISE MYSELF to give so much time and energy to improving myself that I have no time to critisize others.

I PROMISE MYSELF to be too large for worry, too noble for anger, too strong for fear and too happy to permit the presence of trouble.

I PROMISE MYSELF to think well of myself and to proclaim this fact to the world, not in loud words but in great deeds.

I PROMISE MYSELF to live in the faith that the whole world is on my side, as long as I am true to the best that is in me.