Why do people find me intimidating? Is it because of how I look or something?

I have a face that looks stressed, tired and angry. I'm depressed most of the time and I just hate my own life. But I don't understand why other people think I have a problem with them. I had an incident where 3 girls attacked me because they thought I was trying to mess with them. I had another incident where a grown 6'1 man asked me what my problem was because I just made a quick eye contact. I don't understand why people won't mind their own business. I definitely don't have staring problems. I mind my own business at all costs and I never try to start stuff with people. What is their problem? Is it the way I look?