"Partisanship is our great curse. We too readily assume that everything has two sides and that it is our duty to be on one or the other." - James Harvey Robinson
A trait that most humans have inherited is the mentality that everything can be split into clear-cut segments. Unfortunately, this is one of our greatest faults as a species. The truth is that most things do not have finite distinctions, and failing to recognize this can be dangerous. Succinctly, people must find balance in everything they do, otherwise everything can topple over to one side.
Balance in Life
A simple example of striking a balance in life is when one leaves time for both work and play. As I said before, there is never a clear distinction between things, so work can easily become play and vice-versa. However, if time is only spent playing, for example, nothing is accomplished. Similarly, if one works all the time, there is no time for rest, which is also detrimental.
The same goes for everything in life: there is nothing wrong with eating unhealthy foods as long as it is balanced with healthier ones; watching TV is fine as long as there is some time spent doing physical activities; leaving time for oneself is important, but it must not take away from time spent with others; etc.
If ever you are distressed by a problem, try to think of it in terms of balance: if you have been doing a lot of one thing, have you done enough of the other? People are often surprised when they realize that much of their stress can be alleviated by simply incorporating a balance.
Balance of the Mind
We also tend to split things into groups mentally. Black vs. white, male vs. female, wrong vs. right, liberal vs. conservative, etc. This is another fault many humans have. By thinking in terms of one extreme versus another, we exclude a very important grey area. Historically, this need to distinguish and discriminate is what caused a lot of suffering.
Adolf Hitler was responsible for the near extinction of the Jewish population because he believed they were as a whole intolerable. African Americans had to fight for freedom and equality because of the same narrow mentality. Women, homosexuals, Irish, Tutsis, and many other communities have struggled, often sacrificing their lives, in an attempt to change this extremist frame of mind. Because of the immense sacrifices these groups had to make, it is difficult to believe that all that was necessary to better their conditions was for people to recognize that they are not really that different from each other.
These extreme cases only illustrate the point that imbalance, though relatively easy to correct, can be hugely damaging on a larger scale. However, thinking in simpler terms is just as important. For example, wheat bread is thought to be healthier than white bread. Though this is generally true, certain kinds of wheat bread are not whole wheat and contain a lot of added sugars. In other words, don't take one thing and assume that it is the same as all the others of its kind just because it is not the other extreme.
Striking the Balance
Remember that very few things (if not nothing at all) can be separated into finite categories. Try to think of things more as a spectrum. Recognize what you already have in your life and then try to create more of a balance by adding elements you don't have much of, or removing elements you have too much of. This will help you in just about every aspect of your life.