If a person is optimistic and believes that stocks will go up, he or she is called a "bull" and is said to have a "bullish outlook". A bull market is when everything in the economy is great, people are finding jobs, gross domestic product (GDP) is growing, and stocks are rising. Things are just plain rosy! Picking stocks during a bull market is easier because everything is going up. Bull markets cannot last forever though, and sometimes they can lead to dangerous situations if stocks become overvalued.

If a person is pessimistic, believing that stocks are going to drop, he or she is called a "bear" and said to have a "bearish outlook". A bear market is when the economy is bad, recession is looming and stock prices are falling. Bear markets make it tough for investors to pick profitable stocks. The best strategy is to wait on the sidelines until you feel that the bear market is nearing its end, only starting to buy in anticipation of a bull market.

Chickens are afraid to lose anything. Their fear overrides their need to make profits and so they turn only to money-market securities or get out of the markets entirely. While it's true that you should never invest in something over which you lose sleep, you are also guaranteed never to see any return if you avoid the market completely and never take any risk.

Pigs are high-risk investors looking for the one big score in a short period of time. Pigs buy on hot tips and invest in companies without doing their due diligence. They get impatient, greedy, and emotional about their investments, and they are drawn to high-risk securities without putting in the proper time or money to learn about these investment vehicles. Professional traders love the pigs, as it's often from their losses that the bulls and bears reap their profits.