for me its at work around a group of people, under pressure, stressed, lots of responsibility and for me its a heavy weight, some people can just be relaxed all the time ... causes me to be inwardly terrified ...
on the train i am very anxious. if you look forward then you have all these eyes peering in your direction, so you have to either look down or to the side which can be just a really strange experience in itself. just alot of people sitting there waiting to get somewhere in silence.
usually around authorative, arrogant, "show off", "know it all" socialite type people make me very nervous because often they are needy and attention seeking at the same time plus they have overwhelming confidence. hard to be around and makes me very anxious.