Encountering any stranger is bad enough, if it's someone in the street, the supermarket, or in the gym, who will never mean anything to me at all. I ignore them, but I feel rude. It's not worth any effort. It's better for them and for me to say / do nothing.
Much more important is people I meet via others. I feel under pressure to be friendly and incorporate people to my world. I form a summary of new people in about 5 seconds. Everyone does. My logic is to dismiss anyone unless we have a lot of things in common. I met new people regularly over the last month through an old mate. I knew in 5 seconds they'd mean nothing to me. I gave them a lot of effort over the month. At others' homes, theirs, many times, and finally a BBQ which I organised and paid for. They live right opposite me in a different apartment block - closer than anyone else I know. Since that BBQ, we have never met, and we never will, and that includes the friend who introduced us. Never again. I'm still waiting for someone to tell me why this happens over my entire life of rejection.
Much worse is meeting in interview - boss, colleague, HR bird, etc... 5 seconds, and I can tell we won't get on, and I can tell that they will feel exactly the same, at the moment when I say something, or I answer a question and it puts everyone off, for a reason I'll never understand why, which sends me into a twirl in my head for months searching for a reason. If I do get success, and end up in a new office later on... the ultimate worst is meeting all those people around me. Maybe a few days of that when I can tell it's not going well. If lucky, I can get a few more weeks carrying on that that, ignoring everyone, doing a good job. When I get fired, I'm sure it's because we don't get on; I will never know why that is. I'm not willing to giggle with gleeful LOL people, having group hugs.
Hope that cheers you up