I too have never used a knife as a self-defense tool. I have used a knife as a tool for cooking, fishing, cutting open boxes, etc. However, I don't blame anybody who carries a knife for self-defense and for nothing else. By the way, I'm 37. I would not be able to out box (or outrun) the 21-year-old version of me. I would need a tool to cheat and defend myself. A knife is always on me, so that may have to do.