No people don't usually seem scared of me, and they never have. Only times I've ever alarmed people is when they've tried to push me around too much or started hassling me, and then I've been known to (metaphorically) shake them a bit, which is called getting angry, and I suppose that's what anger is for. I just do that to get them to back off. One bloke in a supermarket came up and demanded I apologise for clipping his trolley, which I don't think I did, so I wouldn't apologise. He threatened to "get me outside" if I didn't, so I said I'd get him if he didn't shut up, and to my surprise he left me alone.
My appearance has never been physically intimidating except when I took a few stern-looking selfies of my face just for fun and somebody remarked "do not spill this man's pint." Only a photo of course but I suppose it proves I can look threatening.
I've been known to feel a tad scared of some other people, usually on dark nights, often on the streets in the inner-city area where I used to live, which is probably just realistic. Some of them do look like they're going to go ape. I don't go out at night alone much these days unless I really have to, and then if I pass anybody who looks at all menacing I try to look a bit tough and decisive. No idea whether it works or not but nobody's ever attacked me, except one weirdo who extended his hand as if to greet me and then at the last moment punched me as hard as he could on my forearm. I was so surprised that I didn't think to retaliate till he'd gone, but we met later, in the daytime - he demanded money, I told him sternly to keep away from me, and he backed down.
Another time in a public toilet in the town centre this bunch of yobbos showed me a knife. Then one of them said "do you want it? It's been in seven bodies." Another said "he'll need it." I said "no, I'd better not, I'd only get into trouble," and gave it back. I left the place, and it was only after a few minutes that I started feeling anxious. I still don't quite know what their game was. I guess they were trying to scare me, which they did, only not quickly enough for them to notice. I've no idea what they'd done if I'd panicked while they were still there.
Needless to say, it's usually men who make me feel intimidated, but it hasn't happened much. Most men just mind their own business but you can't be too careful.