As I understand it, Aspies tend to approach people to try and form friendships, whereas HFAs prefer being alone and don't tend to care about friends. Overall, though, Asperger's and HFA are very similar, to the point that some people use them interchangeably.
I have had trouble recognizing when I'm stressed, sad, etc. I only am able to recognize it when it's in the extreme. Even then, I sometimes misinterpret it. Usually, I try and mimic the emotion I think I'm supposed to feel at something, which has caused me to be not very well liked at times, or for people to misjudge me.
I don't know how one would go about gettin more emotional awareness. Personally, I don't care. I like the fact that I am normally dispassionate. I like the fact that it helps me to not take the Rashomon Effect to the extreme, like far too many people do.
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"Let reason be your only sovereign." ~Wizard's Sixth Rule
I'm working my way up to Attending Crazy Taoist. For now, just call me Dr. Crazy Taoist.