The mind is a much more powerful weapon than the fists. Effective use of fists might blacken an eye or break a jaw, but effective use of a mind can ruin lives and destroy the world, or save lives and benefit the world.
The feet. They're great for running away.
Always remember that "flight" is the first response to "fright" in the four f's of survival: Fright, Flight, Fight, and Procreation.