Availability error

Availability error, related to the gambler's fallacy, is the distortion of one's perceptions of reality due to the tendency to remember one alternative outcome of a situation much more easily than another.

For example, if surrounded by slot machines people are more likely to continue feeding money into their machine, because they will occasionally see someone else win and think their chances are high of winning: they remember others winning much more readily than they remember all the times they and others have lost. The fact that somebody has won does not change the actual probability of winning, and concentrating on the number of wins fails to take into account the number of losses. People consistently make this mistake, even though the odds of winning are just as bad for the group as for the lone machine. It's just easier to remember winnings in large groups than for the lone machine.

Other examples:
 * "Sorry I'm late -- I hit every red light on the way here."
 * Anti-"country X" sentiment escalating due to occasional unethical actions of country X.
 * "My friend is a choleric, a typical Aries". (the person does not remember hundreds of untypical Aries he has met that were not choleric and falsely believes in the relation between character and the Zodiac Sign)