One of my final professors in college taught us to ensure that when looking at a position to examine both sides of every side, and if we want to be very thorough, to look at both sides of both sides of either side.

It's a lesson that has stuck well and has helped me maintain perspective in a wide variety of situations.

The old adage (I believe from the ancient Asian philosophies of Taoism and Zen) "Think thrice before you speak, and then only speak if you have thrice concluded it is worth hearing" is another way to keep yourself in check at times. How many times have I wanted to speak and realized some folly in my thought process!