It is impossible of course to provide an entirely satisfactory explanation for any recreation. The predominant motive in any human activity varies according to the temperament of the individual. Mountaineering provides good exercise in pleasant surroundings, a sense of satsfaction in overcoming difficulties, the joy, akin to dancing, of controlled rhythmic movement, a stimulating contact with danger, a wealth of beautiful scenery and a release from the tiresome restrictions of modern life. The expert likes to practice or display his skill. Some confess to having been drawn to climbing by a physical inferiority complex engendered by their failure at school to hit a ball straight and far. These motives are probably sufficient in themselves, and they certainly form the basis of many other sports. But in the deep devotion to any form of active endeavor there is generally something else we seek. In the case of mountaineering it is a kind of personal identification with the hills themselves, which comes of intimate understanding and strenuous contest and which brings with it a wealth of philosophical content. Above all, in my view, the attraction lies in the memory of those rare moments of intellectual ecstasy which occur perhaps on a mountain summit, perhaps on a glacier at dawn or in a lovely moonlit bivouac, and which appear to be the result of a happy coincidence in the rhythm of mind and scene.

From Upon That Mountain.

Pretty much sums it up.