Whatever you are consistently focusing on, determines your mood. Majority of this theory has been taken from Anthony Robbins and flourished with my thoughts/ideas.
For example, pretend that you are at a party with a video camera, and you are constantly video-taping a couple fighting with each other. The moment you leave that party, you will think to yourself, "man, that party was intense everyone was fighting, no one got along." Or, if you record people doing keg-stands all night, you will leave the party thinking that it was a debacle.
Another example that strengthens this theory is the following: For the next 20 seconds, look around the room, and look for everything that is brown, then close your eyes. Although, you probably can't read this with your eyes closed, after you look for everything brown, name all the things that you saw that were green. You got tricked. This is the same principle with focus. When you focus on the brown in life (the feces) you will miss out on the green (the real life).
What does this mean you ask? It means that when we focus on one thing so intensely, we delete other things, and put ourselves in the state of what we are focusing on. We tend to delete or just forget about things that we are not focusing on. So, how should you start focusing on other things? The answer is simple, ask yourself the right questions.
Have you ever been in a situation where you ask yourself, "why do I have to do this" or "why me"? Well, these diabolical 'why' questions only put you in a deeper state of frustration and anger. Next time you are in one of these situations, ask yourself, "how do I complete this job, and learn from it?" or "how can I enjoy this process?"
Whatever you ask your brain, it will find the answer to.
Negative Question : Why am I always so tired? Answer : Cause I stay up late every night.
Negative Question : Why am I always late? Answer : Cause I don't have my priorities straight, and can never make up my mind in what's important.
Positive Question : Why am I so lucky? Cause I have a positive attitude and am willing to take risks.
Positive Question : Why do I have such great friends? Cause I am very selective about who I associate with, and am a great judge of character.
Therefore, if you want to learn from every situation, ask yourself the positive questions. What can I learn from this situation? What do I respect about this person? What's funny about this that I don't notice? Why is my life so great?
Have fun with your mind, and enjoy.