Here's a great quotation from Elder Richard G. Scott's 14 August 2008 Commencement Address at Brigham Young University:

"Radiate a positive attitude. Let your attitude be that of continuing happiness. The challenges you face, the growth experiences you encounter, should be like temporary scenes played out on the stage of continuing peace and happiness. Don't become so absorbed in a single event that you can't think of anything else. Challenges are not intended to be the substance of life. It is by understanding and obeying the teachings of God that your life will fulfill its glorious purpose. That perspective keeps challenges confined to their proper place -- stepping stones to further growth and attainment. Life should and can be wondrously beautiful."