School ground stuff is a wank off anyway,avoid them ,just laugh at them shake you head and walk.

But that problem is a real one, if your threatened outside by an unknown assailant.

Not wanting a confrontation in the first place ,plus adrenalin usually equates to a fear thought entering your head.
Either fear of what can happen to you or them.

The only way out of it is to know this, think about what happens if you go down and the fight doesnt finish there and your never the same again or worse still.
Your family are ripped off and live the rest of lives in misery because you chose not to go all out!
either running or fighting for your life.

Running is so much easier ,if the fool catches you,even on another day, its his bad luck then.

Aviodance can come easily.
#1 If you smile big, the whole time they are threatening you, it dissengages their will to fight.because they are expecting you to be demoralized by the threat.
It helps to control your adrenalin too a smile helps your own mind to stay clear even in adversary!

#2 If you ask them how much money they have in their wallet?
they always frown and ask, "why?"

And your answer is 'I will match it dollar for dollar and we meet at such and such a gym or dojo .

End of fight right there because you have outsmarted them by bringing in another unseen and very serious option (that you are fully prepared to go ahead with) that they cant really think about clearly in the situation that they have caused.

Ive used that in Pub situations twice against massive men and had beers bought for me instead of having to damage them for life.

Another adrenalin control is, To know you are safe ,You must be in a relaxed even balanced front stance, have your groin covered by turning in your front toe and knee slightly and have your chin down a bit and hold it (like your thinking) between your thumb and forefinger and your other hand is resting on the inside of your elbow so you are covered high and low and you have a vertical fist ready to strike out or block if needed. realise that your open only high and to the outer,its an easy straight smack out , if they are dumb enough to open themselves up and go for that one.