From yet another good article by Shankar Vedantam:

Winners discount information about lucky breaks and chalk up their right calls to superior judgment, whereas losers tend to emphasize the role of bad luck — rather than bad judgment — when their predictions go wrong.

Thomas Gilovich … said this is why a lot of water-cooler conversations among NCAA office-pool participants feature people explaining to others why their predictions went wrong. People don’t talk very much about predictions that went right, Gilovich said, because they automatically chalk up those results to brilliant insight. Wrong calls, however, are invariably seen to be caused by fluke events — which is why they need explaining. …

When psychologists once asked sports fans to visualize how a particular team might win a game, the volunteers became far more likely to later believe that the team would win — and to bet money on it. Essentially, psychologist Bryan Gibson of Central Michigan University said, focusing on some part of a conundrum makes it much more difficult for people to keep in mind how much they do not know about all the other variables involved. …

Gibson has also found that gambling is one domain in which it may be wiser to have a pessimistic personality rather than an optimistic personality. Gamblers tend to be optimists in that they inherently believe good things are likely to happen to them. When a pessimist wins a bet, he is likely to walk away with his winnings because he can’t believe that his lucky streak will continue. … optimists were far more likely to throw good money after bad because they believed that, sooner or later, things would break their way

To do better:  focus more on explaining why you won, than on why you lost.