Also known as: "The Slightly-Less-Than-Optimal You"
You, as an individual, are the weakest point in your self-defense arsenal. Your lack of confidence and self-doubt make you an easy target for any would-be attacker.
When confronted, you will likely freeze, stumble, or make a poor decision that puts you in an even worse situation. It's a classic move, and one that will get you defeated every time.
For more on how to improve your defensive skills, check out Weak Point 3.2: The Fumbling Frenzy
Or, if you're feeling particularly adventurous, try Weak Point 4.1: The Incoherent Cussing and see if you can handle the consequences.