When my younger brother would rarely get super angry and physical with me, I didn't do anything either. I think it's got nothing to do with strength (to be fair I've accidentally hurt him too before due to not knowing my own strength), it has more to do with Aspies not always having the ill-will to direct their strength against others. Lifting a couch is one thing, potentially hurting a person is a completely other. On top of that, if someone suddenly charges me, I would have problems knowing how to react exactly and might freeze up.
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After years of self-imposed exile. I am now making an effort to talk to people. So anyone feel free to PM me on any subject, I would love to try to interact with people more!