Have you taken algebra?
When is the last time you used algebra?
My daughter is currently doing Algebra and I don't have any clue how to help her and I have not used Algebra since I took it in High School.
Have you taken some form of self defense?
Have you had to use that self defense?
Was there a time when you wished you had learned Self Defense?
Most of us don't think about algebra until something comes up that we might need it. The same goes for self defense - we don't think about it until we need it.
Under stress we revert to our lowest level of training. If we have not had training, we often end up with panic. Unfortunately because of panic, we often end up our worst enemies if we survive a violent encounter. We then think about what we should have done, what we should have said, what we could have done, other options and we end up beating ourselves up.
With training we can stem off a lot of that. There is no training to keep you safe from every what if, but training will give you a fighting chance.