If you see someone you know in a public place and they're talking to someone else (someone you don't know well) do you go up to them and interrupt their conversation to say hi?
I have been beating myself up about this (probably needlessly) because I think that it's a problem with me that I feel embarrassed approaching people, even if they are my friend in a situation where I haven't already arranged to meet them or where I have seen them spontaneously. I just seem to have this really heightened anxiety about not wanting to intrude, or encroaching on people's time when they have not set it aside for me already. Especially when they are with someone else.
Am I correct in my hunch (very strict upbringing where I was brought up to think I was always wasting other people's time) or do people do this all the time?