One of the most important--and consistent--rules of life is that life gives to us what we give to life.  Emerson said, "We find in life exactly what we put into it."  Many others have noticed the same dynamic and have documented its truth very well.  If this is the case, then the pessimist is involved in thoughts and behavior that almost guarantees his or her misery.  If I'm sure that I'm not going to get a certain job, for example, that's going to affect the way that I interview and thus lower my chances of actually getting it.  If I think a person is going to hurt me, then I'll subtly treat that person differently, and guess what?  That person is going to do something (perhaps avoid me), thus "proving" that my pessimism was justified!  Of course, I won't stop to think that my own actions that resulted from my thoughts actually caused the reaction from the other person.

We usually pair the concept of pessimism with that of optimism in order to compare them, as if they're two opposites.  Rather than seeing them as "opposites," though, it may be helpful to see them simply as two different ways of thinking, just as walking and riding a bike are two different ways of getting to a destination.  The major difference is the quality of the journey--the optimist goes through life creating, filled with and surrounded by positive energy, while the pessimist tends to create negative energy that fills his or her life and keeps the person focused on the negative.

The pessimist will argue that he or she isn't a pessimist, but a "realist."  After all, many negative things happen in life, and this person thinks that it's justified to focus on the bad as a way of life, as a way to shape and form his or her own perspective on life.  Their version of reality, though, includes only a very small portion of what truly goes on in the world and ignores all the positive things done every day.  Pessimists view the good in life as exceptions rather than the norm, and by maintaining this perspective, they guarantee that they will continue to be pessimists.

Pessimists remind me of people who do only enough research to prove their own points, using only sources who will support them.  They can read a 200-page book on the joys of life, and focus only on one sentence that might say, "Yes, there are bad things in life."  This kind of research, though, is universally condemned as invalid and self-serving, and it's never accepted as valuable research in any field.

If you wish to create many negative experiences for yourself in life, then by all means, adopt pessimism as a way to look at the world.  Be aware, though, that your perspective will be anything but realistic, and that many of the negative things that happen will occur because your perspective actually caused them.  Nobody's saying that everyone should be outgoing optimists, but it is true that an optimistic outlook on life helps us to meet more optimistic people and to encounter more positive experiences--and recognize them for what they are when we do encounter them.