Answer # 7 comes closest for me ("to test your own self"), as to why I started, but not why I stayed (8 years continuous, as of October 6.)
I considered myself a well-rounded individual spiritually, intellectually, socially, artistically and creatively, but I knew there was a hole in my makeup, and that hole was: "physically".
At 5'6" 150 lb. I wasn't really able to do much as far as self-defense was concerned, so I studied and carried a variety of personal weapons.
However, that's not an ideal thing, as these can be lost, taken away,left at home or undeployable in time.
Plus, it really doesn't solve the personal problem of physical inadequacy -- perhaps it even highlights it more.
So after many long years I started at age 47.
But my reasons for STAYING changed.
Once the novelty wore off and the reality of physical encounters, Karate or not, set in, I grew more and more interested in the training and how it was creating a physical and mental transformation in me, not to sound too overblown.
I just can't leave it now.It's become such a part of my self-identity, and I feel physically wonderful after a class, and the next day too.
My abilities have grown, my fear of physical encounters is on a leash now, and I feel like I've "filled that hole" at least partially.
The music spoke to me. I felt compelled to answer.