People play many ways for many reasons. Some log into their account each night in pursuit of more vanity pets or achievements. Others log in to blow off some steam in the battlegrounds. Personally, I keep paying my monthly fee to Blizzard because I'm hooked on min/maxing.
For those who don't know, min/maxing is the practice of minimizing your character's weaknesses and maximizing their strengths. In the case of my rogue, this mostly represents a continuing effort to do as much damage as I possibly can to a single target for an extended period of time. I see this as the primary role of a rogue in PvE, since there is little else we can bring to a raid which benefits others. We have no meaningful group buffs. Our CC has very limited applications. Blizzard intentionally designed our class with only one purpose in mind - hurting bosses.
It is for this reason that I feel it is my responsibility to min/max. I feel that a rogue is a bit of a liability to group, as they tend to get hurt easily and have little else to offer besides dps. I feel that unless my damage output outweighs my intrinsic risks, unless it outweights the benefit of bringing another class of greater overall utility, then I can't justify my presence in the group.
Now, I understand others don't see things the way I do. They may say they just play to have fun. Or they may say they play the spec that feels the most natural to them. I don't begrudge anybody the right to play the way they choose. I try not to pass judgement on others for not doing things "my" way.
However, it should be noted that the difference between these people and myself, is that min/maxing is how I have fun. I have more fun going over spreadsheets and loot tables than I would have inside the game shadowstepping up to a mob. It's more fun to me to see a jump in DPS on a target dummy than it is to blow killing spree.
I see the talent trees, gear, gems, all these things as a means to an end. If I believe combat will yield better damage than assassination, then I will change specs. A boss kill is less meaningful to me than a bit of insight gleaned about my class on how to squeeze out a bit more damage per second.
It is with this attitude that I approach the game. While some may sneer at those who jump on "cookie-cutter" or "flavor of the month" specs - I think this is anti-intellectualism. There is an axiom that says DPS is a science, healing is an art. I can assure you, DPS is in fact a science. There is always an objective, empirically measurable, theoretically describable method for maximizing DPS. For Burning Crusade, it was 20/41. For Wotlk so far, It's been HaT for stacked groups, Assassination for standard groups.
I believe the difference between an average player and a great player is their ability to adapt. I think part of the reasoning behind the anti-intellectual spec-bashing is that some players are either unable or unwilling to adapt to the class changes that Blizzard hands us. For instance, combat is a perfectly viable (though not optimal) tree at this point in time. However, Combat Swords is not. There are legions of rogues who have failed to make the necessary changes that came with the most recent expansion. They are still camped out behind bosses, hitting their sinister strike key three times, refreshing SnD, hitting SS five times, and refreshing rupture. All the while other classes continue to climb higher and higher on the damage meters until, ultimately, they reroll death knight.
I know I'm not the only one who has noticed the sudden, massive disappearance of rogues and the huge influx of Death Knights.
It has always been true that most rogues suck. The nature of the class has always been the most appealing to young players with short attention spans, little patience, and button-mashing mentalities. Once a little finesse became necessary for optimal performance, the lack of talent among the rogue community quickly became very apparent to WoW at large and, in between crying on the official boards about how difficult it is to refresh hunger for blood twice a minute, rogues at large were working on their new death knights.
It has happened multiple times now, where I'll join a VoA pug and find another rogue in Valorous gear, theoretically capable of pushing out over 5K dps in a heroic raid, and I'll smoke them in the charts. My gear is not fabulous. In fact, my output is rather laughable compared to what some of the heroes in the rogue community are reporting, but even so, I've been able to scream past every other rogue I've ever grouped with, except for one.
While other players are content with mediocre performance, or just not talented enough to roll with the changes, the min/maxing rogue will always be there, blowing the mediocre players out of the water and showing the community why there's still room for us in their group.
This is how I play. This is why I play.