I disagree slightly that fun is directly proportional to the player coming back or being addicted.
It definitely is a large piece of it - but not all.

Take for instance a multiplayer game against your friend.
He keeps beating you, and you get annoyed.
Some people (like me) may keep trying against the odds to get better than him - you don''t want to allow him the satisfaction.

In this case, its not as much about the game being fun, but about the competitiveness of multiplayer.

This might be a bad example, but Im sure everyone gets the idea

Here''s my two cents on the subject.

First of all, I think we all agree that different people with different personalities probably have vastly different addiction patterns. What may excite one man and make him play a game repeatedly may just as well disgust another player. So to create a game addictive for EVERYONE is... well, an impossible task.

It''s all in biochemistry of the brain. Some people like the adrenaline rush of a fast car game. Others may not. We like adrenaline because we lead less thrilling lives than our ancestors, and have a constant feeling that something is "missing". Some people prefer mental challenges of a Myst to a Need For Speed experience.

One other thing is the question of reward. I agree completely that a player must NOT be stimulated too often. Indeed, physiology knows a term called "habituation", which means that a person feels less and less pleased if the reward is continually repeated. What is even more interesting, particularly for this discussion, is that punishment stimuli are not habituated. A wise designer should use this to his advantage.

But that is where most games today lose their compass: I can save game everywhere, so I am not too much afraid even if my character does die. But, if I forget to save and get killed, I will become frustrated because I have to replay a large portion of my game (considering the game is linear - and it almost always is). So, what to do?

Imagine a game which comes on a rewritable CD and the player has a CD writer. You buy the game for $1
0 or whatever and install it. No save-games. When you quit the game is saved, when you restart the game is auto-loaded. When you die, the game commands the cd-writer to destroy the CD.

Of course noone would like to spend precious money just to lose it quickly. The game would be sold poorly, if at all. But at least I can guarantee you one thing: MAN, would people be cautious about their character! MAN, would they gasp with every sword swing/bullet shot in the character''s direction. MAN, would they sigh in relief after they win a battle.

I''ve got a few arguments to back up my claims. Remember tamagotchi? it worked on the same principle. Oh, and a version ov Pong that does not count points but instead causes the player who receives the goal to suffer pain (his one hand is tied to a device that causes electric, heat or mechanical shocks) is curently pretty popular, I hear.

I have a feeling I said way too much already. More to come on this topic... if you want.