Oh well - is probably the most optimistic comment of the extremely gloomy donkey in Winnie the Pooh. My concept of Eeyore is that the blue/grey donkey is always dwelling on the negative events in his life (losing the tail). Whether it is a past event (memory) or future expectation, Eeyore is slowly between monotone sighs, verbally singing the blues of his woes. His name even sounds tired and depressed.
Mood affects memory and memory affects mood - says Dr. Richard Wiseman in his book, "The Luck Factor". In fact this two way relationship can become an infinite spiral down - like Eeyore's attitude. So how can this spiral (which anyone can begin to have on any given day) be broken? I think there are two ways - put the bad past behind you (e.g. forget about it; let it go) or change the view of the past event by putting a positive spin on it (even if it means just saying - "it could have been worse".)
(2) Watch a funny film
(3) Spend time thinking about a positive event (distract yourself)
(4) Listen to your favorite music - well maybe not Randy Newman :)
(5) Arrange to visit a non Eeyore friend
By the way remember #5 when you are with a friend!