Rabbi Simcha Bunim taught that every person should carry two pieces of paper, one in each pocket: in one pocket "For me the world was created." and in the other "I am but dust and ashes." When we have moments of self loathing take out the first; in moments of grandiosity the second. Our souls are poised between greatness and nothingness; in knowing both are we blessed.
Try putting these two pieces of paper in your pockets for the next week. How does it impact your decision making? How does it affect your perspective?