A number of articles on the web cover the topic of "why we play board games", as do a number of books. I have read many of these articles. Unfortunately, due to cost constraints, I haven't read most of these books (but my birthday is coming up, and my wantlist is on Amazon, hint hint).
In a recent Gone Gaming article I wrote how the answers to the seemingly straightforward question - "Why do we play games?" - are not really straightforward. We often want to play one game today, and another one tomorrow. We may want to play games at 10:30, and watch a movie at 11:00. So I posited that the "reasons" why we play board games are really a complex interaction of variable "factors" that contribute to us wanting to play at any particular time. These factors depend heavily on our own personal psychology, recent events, our culture, and present and past game groups.
Yet, even not considering the complexity of these factors, the reasons given in the articles that I have read seem to be woefully incomplete. I could assume that other reasons are given in some of the articles and books that I haven't yet read, but I find it strange that all the articles that I have read on the Internet pretty much overlap; surely somewhere someone would have mentioned a few alternative reasons for wanting to play games other than the classically presented ones.
A classic example is the online text, The Art of Computer Game Design, by Chris Crawford, which lists the following reasons (additional annotations are my own):
Escapism - People want to distance themselves from their current reality. This is certainly true, and it also holds true for other forms of entertainment, from watching movies and reading books to simply walking or having a conversation.
Nose thumbing - The opportunity to simulate non-socially acceptable acts, such as killing people or stealing things, within a social acceptable framework. Again, also a reason that people watch movies, read books, and act.
Proving Oneself - By means of competing against your own score on against others in a ranking system or in a tournament. This provides self-satisfaction.
Social Activity - Either directly, during the game itself, or by means of having a common experience to share with others while socializing.
Exercise - Although chess players may break out in a sweat on occasion, I believe that this more refers to sports games, rather than board or computer games.
Acknowledgment - This is the counterpart of proving oneself: hoping that others will acknowledge your mastery or your efforts, thereby stroking your ego.
This is a nice list, but I think it hardly scratches the surface. It certainly misses a whole host of reasons that I know that I, and other people, play games:
Appreciation - A fine game is like a fine piece of art. I know that there are games that I've played just to learn why they are popular. Similarly, I have played games for the experience. Part of the joy of learning how to play Go is to appreciate the subtle beauty of the rules and the components.
Some people I know like to read rulebooks. And I know someone who learned how to play Bridge so that he would be able to understand the Bridge column in the newspaper.
Creativity - Many games reward creativity. Whether a party game where you have to come up with a synonym for a word that rhymes with 'snake' within five seconds, or a strategy game where you need to try something devious and unexpected, the opportunity to express yourself creatively is a pleasure that specifically drives people to play games.
This is the same impetus that drives people to paint, write, or act. Sometimes, when the opportunities for creativity are no longer relevant in a game, the game is no longer enjoyable.
Cooperation - Perhaps closely related to being a social activity, I still think that this reason deserves its own mention. That is because you can experience cooperation entirely non-verbally. Rather than being a social reward, you can think of this as a reaffirmation of humanity and kinship.
The concept of cooperation does not require a cooperative game. All games are essentially entirely cooperative. A Chess game requires two players to cooperatively adhere to the rules and spirit of the game in order to create the game experience. It always takes two or more to play a game of any sort, not including puzzles or solitaire. Cooperation is its own sort of reward.
Education/Inspiration - These are related concepts, I think. Many games give to us as much or more than we put in. It may be a game that stimulates your creative juices, makes you think about a subject, or gives you ideas for your own game designs.
Many teachers use games in their classrooms just for this reason. Namely, as a springboard for a topic related to the theme or mechanics of the game or gameplay. Children for many generations have learned Chess and Go as instruments for intellectual growth.
Gambling - This is surely the oldest and most prevalent reason that humans play games. Every flip of a card or roll of a die is an act of gambling. The thrill and exhilaration, the very fun for most people, comes from awaiting the results of some sort of luck device. There is something inherent in most people that enjoys this.
Humor - Many games are simply fun or funny experiences. Take out a game of Apples to Apples or Balderdash and many people will soon be enjoying themselves with grins and laughter. Again, this places games on par with other entertainment activities.
Management - Specifically by this I mean managing chaos. Think of this as the breadth-first version of Mastery (below). Many games require you to juggle many different possibilities in a short span of time. Some people really enjoy this, whether they succeed or fail.
Mastery - For some games, analysis is a waste of time. For other games, even good analysis is not going to prevent the occasional "D'oh!" from happening. The only feelings that I remember from playing Princes of Florence are the ones about three seconds after I buy the wrong item.
I guess the feeling here is something akin to mastery. Maybe I won't make that mistake again. This is not about "proving yourself". It is about enjoying the control. Control is a very powerful pleasure. Most of the games that I play do rewards patient analysis and experience. I don't play it to prove this to anyone, not even myself. It's just enjoyable in its own right.
Senses - Many games, from sports to Twister to marbles, either feel nice or look nice. Simply participating in the game can be an experience for the senses. That's pleasure.
Story - All good games have their own story, from the humble beginning to the victorious end. Good games go through many of the elements of a story, including partnerships, conflict, adversity, underdogs, and resolution. This is one of the reasons people don't like games to be ended prematurely; they want to know how the story ends.
Furthermore, the story of a series of games in a tournament, or over a time period, or over your lifetime, is a story in its own right. And of course, there are RPGs, which are, literally, stories.
Therapy - Many games, by virtue of their theme or mechanics, can provide therapeutic benefits. It may simply be the meditation you require after a long day of working, or it may be a game that deals with something important to you or your personal history.
That's a partial list. There are many other reasons people play games, such as revenge, belittling, humoring, love, procrastination, and so on. It doesn't seem to me that these reasons can be so easily wrapped up into only a few boxes. Funny how this isn't more recognized.