Again, its your choice. 99.99% of the time at least. If you really do find yourself in places where people are attacking you without provocation, you should be asking yourself why you can't find something else to do with your time. One thing that sometimes happens is we lose perspective. We hang around people that are quick to fight, for example, or like to go to places where trouble lurks. Since we see it all of the time, we think its "normal". The reality is, most people don't fight, or even come close to getting in fights. You can do the same, but again, if and only if you make the choice.