UK, Great Britain, Holland and The Netherlands
I guess this is something that 'grinds my gears'. Most of this comes from my experience editing a few (relatively minor) publications.The United Kingdom is comprised of Great Britain and Northern Ireland. Great Britain is comprised of England, Wales and Scotland. This is an important difference for a number of reasons.
Similarly we should not, I am reliably told, consider Holland to be a country. It is part of The Netherlands, which is a country.