Merry christmas Jaz.

I think its more a mentality. So pick whatever martial art that lets you develop that; aggression, close-to-real (Sparring) and not to fiddley (realism) etc.

Like when you've been in fights would you say 'the training kicks in' or you just fucking go nuts because you know you can handle yourself which isn't a DIRECT result of the martial art itself, more the training (if that makes sense).

From growing up around it, most of the 'hard' guys were just the psychos and mental like that. Being a psycho,to me, is an extreme end of 'self belief'.