Mental Preparation

From what I have learnt from others and my experience is that mental preparation for a fight or violent situation is often being up for it and ready way before it kicks off. The guy in the car with his wife was already up for it so was one step ahead. When the OP approached he was not.
Natural killer type people are simply always up for it. They don't need a situation to create and build up. Get in their way or cross them and they don't give a millisecond to prepare.....It's 0 to 100.
Or a person is already built themselves up for it and then you come along and cross them and they are one step ahead, while your still responding ...and it's too late.
I think it's worth considering to try to cultivate a mind set of also being up for it and ready to kick off at any moment at a high intensity if it's needed. Instead of having to wait until a situation arises . Obviously it's not about looking for fights or starting things or just responding physically at every situation. It's just being ready to go if all else fails, way, way before.

I'm not saying I am a natural killer type person but I have been around some and seen them in action and learnt that's their mind set.

 

You currently can't deal well with contact, and that will effect you socially as well as martial artsy, undergoing some contact training is exactly what you need.

Boxing, bjj, rugby etc will all help you with that, as well as give you a social outlet for your aggression.