File this under "Pet Peeves" if you like, but one of the things that drives me just a little bit nuttier every time I see it is when people use "USA" as a location for ancestors born, married, living or died before there actually was such a political entity.
Now, I realize I could be accused of being a bit nitpicky over this, but every time I see it, one of the voices in my head screams "THERE WAS NO USA IN 1752!!!!" (or whatever date before at least 4 Jul 1776, which is leeway I grant others - I personally draw the line at the Treaty of Versailles, cause you ain't a real country if nobody else recognizes it).
Likewise, to be correct, I observe the name changes of other countries as well, if I am aware of them; in particular, since I have a lot of Canadians in my tree, I try to follow the timeline between Upper Canada, Canada West, and Ontario, Canada - and note that prior to 1931, technically Canada was still a political entity referred to as "British North America" (pause to duck flying debris from the north :) ).
The British Isles is another example of needing to note the date before recording the "country" name. Germany - well, that's just about a nightmare for me right now, it makes my head spin looking at all the conflicting place names I see ascribed to my Teutonic ancestors - but at least I am aware of the existance of the Holy Roman Empire during some of their lifetimes.
Even within the United States of America after 1783, one has to pay attention to the calendar when figuring out place names. When I started this adventure in family history, I really didn't remember from my elementary school American history lessons that there was once just ONE Carolina, that Kentucky was originally a county in Virginia, and that the part of Louisiana where my ancestors settled was previously part of Florida - thus under Spanish and not French rule until we (the USA) purchased it. I had a vague recollection that New York was formerly New Amsterdam, but couldn't recall when that changed. There are so many more, it's hard to keep track in your head sometimes. I made a chart to help me with some of them, but it needs more work. These things make it easier to research when we learn (or remember) them, don't they?
Ahhh - I feel better having gotten that off my chest. Until the next time I see "USA" on a seventeenth-century immigrant's place of death, anyway.