Studies show that something as minor as the weather can influence how people feel about things totally unrelated. For example, in one experiment, as Fine describes in her book A Mind of its Own, a researcher (posing as a salesperson) gave shoppers a small gift. The same shoppers were later questioned about their opinions on the particular brand of car or television they personally owned. The results were compared to a control group, who were not given the small gift. The group that had received the small gift rated their car and television significantly higher, suggesting that the mood lift created by the gift had a meaningful influence on how they made their rating.

In another test, a group of people were selected to either play or referee a computer tennis game. The selection process was supposed to be at random, but researchers rigged the selection so the subjects always ended up being the referees. The person playing the tennis game was in fact a "stooge."

In the game, there were a large number of balls remarkably close to the line. Prior to refereeing the game, the subjects met the players, and in some cases, the stooge acted in an extremely obnoxious way. In other cases, the stooge acted in a polite and kind way. Guess how those calls that were close to the line went?

When the stooge was obnoxious, she lost a lot of the very close points. When she was kind, the referee called the close points in the favor of the player.

Decision-Making Best Practice #2: Before you make an important decision, check your emotional state. If you are angry, sad, euphoric, or what-have-you, try to postpone the decision you need to make until you are in a more normal state.