How global are global events?
Consider, for example, World War II. If you lived in England or Continental Europe, you could not miss it - even if you were in a serious outback area, chances are that you were affected by rationing, drafting, or troop movements. If you lived in the West of Ireland, though, you might not have experienced much change. Parts of the USA would have experienced little difference for most of the war. Sub-Saharan Africa was probably not much affected, and South America likewise. Places like the Phillipines were definitely altered, but there were probably some Pacific islands to which it made no difference. India? I have no idea.
How realistic is that assessment? Is there a theshold beyond which an event has a (possibly knock-on) effect on everyone? How would you measure it?
And yes, I know there are going to be differences for an interstellar setting. I want to figure out how things work here first.