I have read a few posts recently in the gaming blogosphere about achievements in games. They aren't necessarily referring explicitly to Achievements like WOW or many other games have implemented but rather the broader category of general accomplishments. One example from the extreme edge is Gevlon who collects gold, raids barely competently and spends the rest of his life savagely insulting everyone who does things any other way. There are also somewhat thoughtful people like Pete Michaud in the link above who spend a long time telling people that the things they do in video games are not accomplishments and are not worth doing but do so with much less vitriol than Gevlon and his ilk. The trick is that in nearly all the cases these people simply define whatever they are doing as worthwhile and talk about how what everyone else is into is worthless.
Gevlon is the easier one to mock for sure. He is convinced that he is spending his time well by making gold and raiding and he has no use for people who collect things, try to get Achievements that don't require the specific skills he cultivates or like to socialize in game. He views socializing as utterly worthless and indicative of moral and intellectual failure. Obviously from a perspective of monetary success in the real world nearly all activities in games are useless but Gevlon doesn't even make that distinction - he just insists that it is either his way or you are a moron. Pete is decidedly different. He mocks *all* achievements in games as being utterly worthless. This is a more defensible position but only slightly because Pete has the issue that he basically assumes that things done inside games are not worth doing without any justification for this view. He encourages people to get off the treadmill and have authentic experiences rather than simply hunting for achievement porn within a game.
The trouble with categorizing things that other people do as worthless is you need to establish what is worthwhile. For many people nothing in a game can be deemed a worthwhile achievement because they don't view games as challenging. They might concede that climbing Mt. Everest is an achievement but deny that beating Lich King Hardmode at 0% in WOW is an achievement, for example. The thing is both of those tasks are extremely difficult, can only be accomplished by a small percentage of the population under any conditions and require tremendous focus, skill and practice to complete. Neither task is making the world a better place for others to live in and neither is going to improve one's life except in that they are a benchmark of talent and dedication and in that they are enjoyable to do. Given these things, is there really any argument to be made that one is a worthy achievement and the other is not?
I have opinions about how to rank the worthiness of particular tasks. I do think that there are lots of things we do in our lives that legitimately do make the world better for everyone and those things are really worth doing. That said, we spend nearly all of our time doing things that are just for our own benefit whether they be trivial necessities like urinating or paying the phone bill or enjoyable pastimes like sex or video games. Setting out to declare that someone else's pastimes are worthless compared to your own is dead common and the justifications for that derision pretty much always boil down to "You aren't doing it my way." I think we could all do with a lot more "Well, that wouldn't be any fun for me, but I hope you enjoy yourself." and a lot less of "Why would anyone do that? What a waste of time."