I AM autistic, here's a little story.
>neighbourhood foreign kids throwing pebbles against windows
>they hit mine, I open window and tell them I will give them one warning only
>they do it again
>I storm out in a massive rage, three kids get away, I grab the ring leader by the neck and tell him I'm taking him to his parents
>7-8 muslim teens sitting in a junkfood place nearby instantly run outside to protect their family member
>all angry and shit, they really don't care what's going on and are just looking for a fight
>calmly explain the situation to them, tell them I am really not interested in a fight, children should behave
>they keep getting angrier and angrier while I stay as calm as possible
>one of them gets in my face and puts his eyes in front of mine, people from the neighbourhood crowd around us to see what's going on
>he tells me I shouldn't "act tough" in front of a group of dozen people
>I tell him I am psychotic enough not to give a shit and I'll gladly snap his neck in an instant if he starts anything, even if it means I could die from being beaten up straight afterwards
>people in the crowd quickly rush forward to break us up, a bunch of girls and a few guys get between us and the original troublemakers retreat back into the fastfood place
>kid is crying, cowering behind his mum, before I turn around and walk away I tell her she should teach her kid not to mess with other people's stuff
>turn around, go back home
I actually wasn't lying. I'm not a psychopath or anything, I'm actually an extremely gentle and loving person, very pacifistic. But, if someone attacks me, I go primal.
It's all in the eyes really, if you can convey any sense of insanity with your eyes, people will think twice about fighting you. I haven't been in any actual fight since high-school and have had a few close calls with all kinds of different people but they always ended up backing off. Being /fit/ and being a neuroscientist does help a lot though.