It seems like we come across as angry when we really aren't.
I have been told I looked angry when I wasn't feeling well and was really tired.
I've suffered a burn-out with depression and anxiety recently about half a year ago. Of course this has not just happened but looking back not it has started without me even noticing and gradually become worse and worse.
One of the things that depressed me a lot was that where I worked a lot of people are quite nice, asking others how they are, cheering each other up when they look sad or frustrated, etc. It just seemed to be me who no one cared about, no one ever asked how they were, no one ever tried to cheer up and everyone ignored.
I'm now thinking that probably when I felt totally exhausted and depressed, as I've felt so often for the past few years, I really looked angry. So naturally they would not ask me how I was or try to cheer me up, but rather get out of my way because they thought I would explode in their faces - because that's how I must have looked to them - when I really just wanted to silently cry in a corner. (But of course didn't, because I was at work.)
That must also be the reason why so many doctors and therapists never see when I'm really in pain and never believe me. My face must show a different emotion, because when I look in the mirror I see that I don't look as I always do but really different, when I'm in pain or when I'm sad. But it must be different from what NTs look.