People find it enjoyable for man reasons, they can be challenging, cause adrenaline rushes, be a place of social interaction, allow people to do things they couldn't normally do, and much more.
The first two may not be very er... safe for work, we'll call it.
But yeah, these are small examples of the astonishment games can offer. Some of these are cinematics or not necessarily related to the player, but the game it represents is what counts.
Haha! I wrote about this 2 years ago for my Year 12 major. I won't write ALL of it, in the interests of not going overboard:
The real world is somewhat limiting on what the average person can do with their life. True, people have endeavored to stay as social beings for as long as possible, despite what Facebook and Twitter have done to the meaning of the term "social interaction". Nevertheless, every person, at some point in their life, will find that their life is.... somewhat stale. It needs something extra.
Enter video games. These entertainment products allow an average Joe an escape from reality for a while. A break from all the rules and regulations that are enforced in the world. Want to drive your car at 200 km/h down the I-88? Nope, you get pulled over and charged for reckless driving. BUT! One could play a bit of Burnout Paradise, and work off that excess feeling, at no negative cost to the player. Suppose you wanted to join a Defence force, but you can't (you don't meet the physical requiremente, for instance - or you don't want to leave home - whatever). Want to experience the Army? Call of Duty has a pretty accurate experience. Want to fly a plane? Microsoft Flight Simulator.
It's these experiences that make gaming so fun - the ability to do things in a virtual environment, wherein the experience isn't just handed to you - you need to earn it, in a life-like simulation which can immerse you to the point of actually being there.
Gaming is so fun and addicting just because it is:P well, some kind of goal makes you want to do it over and over again until you reached it. But along comes another challenge, which makes more of an addiction.