The reasons I game have evolved over the years.
When I first started gaming, it was because I enjoyed expressing my creativity in a new and exciting way.
As I got out of high school, and through most of my 20s, it was that plus a strong desire to hang out with friends and people who "got" who and what I was. Around my mid 20s, it became a way to escape the mounting stress in my life, but as that stress went away, so too did the strong desire to escape.
Now that I've started embarking upon my 30s, and I find my oldest child nearing the age that I started gaming (she turns 9 this year), it's not only the two items above, but also a desire to share something that has become so integral to my life with those I love. I feel that I'm developing something of a "mentor complex" with regards to gaming.