But to properly condition yourself is too step outside of ones comfort zone and be willing to face a high level of violence and aggression very frequently in a controlled environment. This is where most people who live a martial life be it by profession or hobby fall short.
Lying crumpled up on the dojo floor or failing a training mission is a confidence killer without a doubt and without a high level of confidence many people will not train. The problem in that way of thinking though is that by training to a lower level then what the fight will be you are being counter productive.
The question you have to ask yourself is to what extent are you willing and capable of saving your own or someone else's life? And are you going to let your sense of pride get in the way of that?