You need a complete system which synchronizes with your body and mind to control any possible opponent before harm can be done to you. What is that system? It's a systematic approach, training, and testing and gaining the confidence that it works.
So what are the worse realistic dangers you can counter in self defense? Simply put someone reaching your pressure points in a split second, controlling your nerves and killing you. If you can master control of all the methods possible and ways to prevent them, then you have mastered self defense.
Realistic is not compromising. What is the worse capabilities of human kind which are knowledgeable and well trained and strive on killing, raping, bullying others?
Simply put, using the element of surprise (taking advantage of the short time that is not enough for a victim to realize he or she is being victimized)reaching the victim's pressure points, controlling him or her and being able to kill him or her. Any other humiliating result is from the psychological effect of feeling controlled by someone else.
If categorized and grouped together consolidated generic methods of attack and defense(reaching opponents pressure points and preventing from them in reaching your pressure points), prioritizations of methods of faster reach and greater impact leading to greater injury, the whole process of training in devastating damage to opponent's pressure points and quick reach to attacking them or stopping opponents from attacking your own pressure points, amounts to twenty one hours of about 200 techniques and 10 training drills taking about 30 hours to learn and drill including an hour warm up for each day out of five days of training 6 hours a day to accomplish this mission. Of course you can tailor your own schedule once your mind is in control and focus on this life saving and confidence gaining mission.
Watch the complete Israel Defense Forces Original Krav Maga 21 Hour Curriculum: