I think there's a potential for anyone, no matter how amazing their life may seem to others, to become bored with it and take it for granted. At some point, that gorgeous woman becomes just your wife. It doesn't help that you've had a couple of fights and disagreements along the way, as all couples do, but no one else sees that. They just think "What the fuck is wrong with him? She's beautiful and nice and smart and talented..." It doesn't matter.
Same with the awesome car, the huge house, the amazing HDTV and surround sound home theater... after a while it's just your stuff. Your awesome car has that one problem that's always bugged you and made it less than perfect. You can't really complain, but it's always bothered you. Your house is awesome, but there's that one issue where at a certain time of day, the sun comes in that one window, reflects off the hardwood floor, and blinds you when you walk into the room. And so on.
Meanwhile there's this virtual other world, this "second life" which is completely different. It's whatever you want it to be, but it also has its own rules and doesn't always do what you might think. It's intriguing at first, exciting to learn all about it, and finally addicting because it's an escape from the life you've grown accustomed to and taken for granted. Sometimes the "perfect" is better than the "imperfect" even if the imperfect is much nicer in many ways. Sometimes just doing or having something different is automatically better.
Now, combine that with a psychological predisposition to obsessive behavior, and you have a recipe for disaster. Not everyone who plays the Second Life has it, in fact statistically it's probably very few. But for those few, it's bad. In a large enough sample population, you're going to find just about every possible outcome, and that includes some guy with a life any of us would love to have ignoring it all to spend his time online.