Know the difference between a Fighting Art and an Artistic Martial Art.
You should always question why you study martial arts; is it for self protection, an artistic form/dance, or to fight competitively? And ask yourself, is what you are studying fulfilling that need for you?
There is nothing wrong with studying either art form, they all contain great characteristics that are not found in others and can fit uniquely to the individual and their needs. As the video demonstrates, the problem lies when a Tai Chi practitioner thinks he can fight MMA, its like saying that the MMA guy can compete in a kata contest with the Tai Chi master or to see who has the most calm inner spirit, of course he will lose its not his craft!
The moral of the story is don't be that guy, don't let your ego get in the way, and don't train blind. Never think however, just because you can do one form you can automatically do the other, theres always a trade off; if your teacher tells you otherwise Id suggest you find yourself a new teacher!
Its our job as instructors to protect you against yourself through honesty, knowledge, and a fundamental understanding of these varying arts. Most good teachers will stop and say "this is more of a kata than a self defence technique"; the dead give away if they are being thruthful is keep your eye on the attacker and question whether he/she is behaving like his intended role in the situation being performed.
Bujinkan to me is fundamentally an Artistic Martial Art form as it is predominately practiced in regards to a feudal Japan battlefield mindset. It can however be adapted into modern forms quite easily; this versatility is what is most attractive about this art and is by transcending the Art and Self Defence boundary. If we do train like this, we however MUST educate our students on how to move and behave as modern attackers and clearly define what the situation and mindset is before we begin, if not we are no different to the fool in the video.
As a Bujinkan student what have you found to be the most dominant training style you adopt and why?