Why is Guitar Hero Fun?

I ask the question in all seriousness. For years, I resisted it -- I kept hearing about this game where you could pretend you were playing the guitar, and how insanely fun it was, and I would roll my eyes and think I DO play the guitar, and it's ALREADY fun. Other guitar players I knew shared my disdain of the game. Trouble was, we had never tried it.

My road-to-Damascus conversion moment came a few months ago, when a friend's holiday party featured an ongoing round-robin session of Rock Band, which for those of you who haven't sampled this particular brand of crack yet is like Guitar Hero, except there's also someone playing fake drums, potentially rocking a fake bass guitar and someone else singing along karaoke-style. Sounds like four times the lameness, right?

Unfortunately for my productivity and self-respect levels, wrong. Totally addictive. Two weeks later I owned my own copy, and started hosting my own Rock Band and Guitar Hero get-togethers -- and suddenly found myself in the awkward, somewhat indefensible position of having no real answer to the question I had so frequently (and sarcastically) posed: why is Guitar Hero fun?

It has something to do with the nature of simulations and virtual reality in general, I think. You already have a life, for instance, so why would you need a Second Life? Lots of people enjoy real tennis -- so why has Wii Tennis proven so popular? Part of the equation is that Wii Tennis and Guitar Hero actually do take some skill to do well (I still can't quite beat the latter on "Expert" mode), but not nearly as much skill as the real thing. So you get the satisfaction of seeing your hard work and practice pay off, only the ratio of hard work to getting better is much more in your favor in the game world than in the real world.

So that's part of it. Another factor is that it's actually a challenge -- even for "real" guitar players -- which those of us harboring an unquenchable drive to excel at everything we do find irresistable. (This describes my wife more than it does me; there was a point at which, after having ridiculed me for getting the game in the first place and having never played guitar before in her life, I would find her practicing Guitar Hero every night -- usually playing Heart's "Barracuda" over and over again. Kill me if I ever hear that song again.)

Also, let me quash a nasty rumor right now: I've heard people claim that being a real guitar player is actually a disadvantage when it comes to Guitar Hero; maybe it's that you want to play more notes than appear on the screen, but at the end of the day some video game nerd might be able to best Slash at guitar in the game world, if not the real world. I think this is hokum: it definitely helps if you know how to play the real guitar!

I feel like I'm partway there, but I don't have the whole answer -- what do you think? Why are simulations like Guitar Hero so damned addictive?