Why Buy A Stun Gun?

Do you carry a stun gun or not? Why do you or don't you carry a stun gun or some sort of self defense product?
I purchased one back in 1988. Why? My reason was because I was riding the metro rail in Atlanta Georgia and did not feel safe without some sort of self defense product. Back then, I only weighed 110 lbs. and felt I could be an easy target for any stranger that would get too close to me. My main concern was walking 2 blocks to where my car was parked from the station. This was especially risky and very scary in the winter months when it was already dark by the time I left my job!
Fortunately I knew someone that knew about stun guns back then and I knew where to purchase one. Women and men now a days might know about stun guns too but have no idea where to buy one. Unfortunately our local superstores or discount stores don't carry them.
What are your thoughts?

Martha