I read a theory once that happiness is designed to be fleeting because otherwise we would eat one meal and then starve to death or procreate once and then die.
Also, related article I read in Newsweek recently:
"If you want to test yourself, take a quick look at this domain name sometimes used by stress researchers: www.opportunityisnowhere.com.
What do you see? For many people, the web site seems discouraging: opportunity is nowhere. But others see the exact opposite: opportunity is now here. When it comes to hidden messages, lucky people perceive more of the world around them. "It is not that they expect to find certain opportunities, but rather that they notice them when they come across them," Wiseman writes in his book "The Luck Factor." This ability (or talent) "has a significant, and positive, effect on their lives."
Also, related article I read in Newsweek recently:
"If you want to test yourself, take a quick look at this domain name sometimes used by stress researchers: www.opportunityisnowhere.com.
What do you see? For many people, the web site seems discouraging: opportunity is nowhere. But others see the exact opposite: opportunity is now here. When it comes to hidden messages, lucky people perceive more of the world around them. "It is not that they expect to find certain opportunities, but rather that they notice them when they come across them," Wiseman writes in his book "The Luck Factor." This ability (or talent) "has a significant, and positive, effect on their lives."
http://www.newsweek.com/id/181290/output/print