Accomplishment. 
  
When looked at video games simplistically, they are all puzzles.  You push this button to solve this problem, then move on to the next one.  The little feeling of accomplishment comes with every successful problem solved.     
Think of it this way, in FPS's you push the trigger to shoot someone then move on to the next enemy to shoot while avoiding getting shot yourself.  In racing games, you steer your car around the track until you finish it, only to do it again with the next race.  In fighting games, you push the attack button to defeat your opponent while trying not to get defeated yourself.  In RPG's there are actually puzzles to be solved while progressing through the story with your chosen character.  In each case, you get a feeling of accomplishment.  In RPG's and other games, the sense of accomplishment is tied into a story which can get you emotionally attached to the character or your own created character.  Every battle is a puzzle to be solved, every quest is a series of puzzles, and every story is a series of quests.  (And the internet is a series of tubes).  
  
The bigger the challenge or difficulty, the bigger the feeling of accomplishment.  Getting to the top of a leaderboard, beating the Nurburgring in Forza, or fighting and winning a good match in MK9 or SSFIV are all great examples.  Personally, beating the challenge tower in MK9 (especially 251) was the last big accomplishment I had in gaming.   
  
 Accomplishment is addicting.  Once you feel it, you want to do it again.  Each kill in an FPS is a mini accomplishment; every match won in a fighting game; every level gained in an RPG.  It's also why achievement points are so popular.  It's just another way of giving people that feeling of accomplishment. 

Maybe it's more exciting than mundane real life. It's entertaining, challenging and fun.

Maybe it's more exciting than mundane real life. It's entertaining, challenging and fun.

I'm gonna say a bit of both for me.  Escapism and entertainment are there, sure, but that sense of accomplishment is most certainly a driving force as well.  

But still, the underlying accomplishment is always there.  Yes, escapism is a big factor which can't be denied.  But there are no games out there that have no purpose, no accomplishment in the end. 

It's just entertainment.  I play games to be entertained.  The last thing I am doing while I am playing video games is accomplishing anything.   Go ahead and ask my girlfriend what I accomplished last Saturday...I guarantee you the answer is going to be "Nothing.  He sat on his ass and played video games all day".  I suppose I am accomplishing the task of being entertained, but then everything you do is an accomplishment to some degree or another.  Nah...you play video games to be entertained and have fun.  If you really feel like you are accomplishing something by playing video games, I think that just means it's time you go out and actually accomplish something.

@TekZero:  
If it wasn't for the fact that you report your length to Girl, Noby Noby Boy would come pretty close to "no accomplishment."

Videogames are interactive, that's why we like it more than movies, books or t.v shows.

There have been attempts to make other forms of media interactive :

• Choose Your Own Adventure books for fiction
• Interactive Fiction video games like the Infocom text adventures
• I'd even say stage / screen experiences like Rock Horror Picture Show live events where the audience is expected to participate.
• TV Shows like Push, NV where prizes and contests are run in conjunction with ARGs
• Heck, American Idol and Dancing With the Stars are examples of Interactive TV that are for more popular (at least according to ratings) then video games.

It's just entertainment.  I play games to be entertained.  The last thing I am doing while I am playing video games is accomplishing anything.   Go ahead and ask my girlfriend what I accomplished last Saturday...I guarantee you the answer is going to be "Nothing.  He sat on his ass and played video games all day".  I suppose I am accomplishing the task of being entertained, but then everything you do is an accomplishment to some degree or another.  Nah...you play video games to be entertained and have fun.  If you really feel like you are accomplishing something by playing video games, I think that just means it's time you go out and actually accomplish something.

@phish09 said:

It's just entertainment.  I play games to be entertained.  The last thing I am doing while I am playing video games is accomplishing anything.   Go ahead and ask my girlfriend what I accomplished last Saturday...I guarantee you the answer is going to be "Nothing.  He sat on his ass and played video games all day".  I suppose I am accomplishing the task of being entertained, but then everything you do is an accomplishment to some degree or another.  Nah...you play video games to be entertained and have fun.  If you really feel like you are accomplishing something by playing video games, I think that just means it's time you go out and actually accomplish something.

I tend to think this way as well. I don't get a sense of accomplishment from games. They are games, after all. I want to be entertained, and either I am or I'm not. I have no doubt that some play games to feel a sense of accomplishment, but that strikes me as a bit sad.

@haggis: But you have to admit that there is some accomplishment in getting a high kill streak or S ranking a game?...

I was thinking earlier this week about how MMOs are often ONLY about accomplishment; that you pay these people a monthly fee (or whatever) to gift you with the chance to do many little activities or a few big ones, which end in, maybe, something you can point to and say that you did that. But they also excel in deferred or even interrupted accomplishment, where you DON'T get loot X and have to do the whole thing over again. Sucks to be you, thanks for your money, see you next payday.
 
Other games though...  while they definitely do have an accomplishment factor, even in MMOs that's not the only thing I get out of them.  I am, in a sense, cheating when I feel this way. What I get can't be measured by statistics.  My favorite moments in most games could certainly be categorized as accomplishments, but the joy was in the moment, not at the end. Like the frustrated justice lurking in the ethical gray areas Sunry trial, or the vistas in Manaan or Tatooine in KotOR (which I've been playing for the second time this past week or so). I guess you could say going outside of Anchorhead was an accomplishment, or turning my eyes to the sandy dunes under the twin suns was, but the tiny happiness I get seeing a virtual world that transports me a bit almost feels like an accomplishment of the game designers more than me. I think this distinction is important, since there's no guarantee one can even find such awe in a game, and they come quite often by surprise, sometimes even accidentally.

That's one reason to play games. A major reason for me is to escape to another world because the world we live in is boring. And to have fun. Cause everybody loves to have fun.

it's interacting with things, fun, there is a story to be told, life is boring. for those people, when was the last time you shot an AUG, ak74, and other automatic rifles, or when was the last time you got to drive a Ferrari. i know i will never be able to drive a Ferrari in my life.

People play games for much the same reason people play sports.

It's different depending on the person. Someone who just buys one game and nothing else all year is playing for the competition. I figure most play for escapism. Video games are more exciting than real life. Many forms of entertainment are for escapism, a distraction.

It's just entertainment.  I play games to be entertained.  The last thing I am doing while I am playing video games is accomplishing anything.   Go ahead and ask my girlfriend what I accomplished last Saturday...I guarantee you the answer is going to be "Nothing.  He sat on his ass and played video games all day".  I suppose I am accomplishing the task of being entertained, but then everything you do is an accomplishment to some degree or another.  Nah...you play video games to be entertained and have fun.  If you really feel like you are accomplishing something by playing video games, I think that just means it's time you go out and actually accomplish something.

I play usually for the story and the expierience-a good game can be as engaging as a good book. Its a mix of excapism and accomplishment. 'excapishment?' 'accomplishism?'

I was thinking this last night over a joint, why I love video games so much. I remembered back to my childhood, seeing Sonic for the first time at my neighbours house and begging my parents for a Master System. 
 
It wasn't accomplishment that captured me, it was something else.