Easiest and Hardest Country to Collect Coins

When collecting by type, which country would the easiest to get all circulating coins? Which one would be hard to complete?

Easiest probably some island nation with 5 standard and commemorative circulating coins, hardest is definently the Roman empire with all of its gold and provincial coins.

If you’re excluding the random european coin here and there with 1 in existence that is.

China is definently a contender too for hardest, with all the fakes going around there would probably be no way to have a complete collection without a few forgeries snuck in.

Most easiest would be the “newer” countries such as most post independence African countries, ex Soviet and Yugoslav nations, with a few island nations thrown in.

The hardest would be ancients and medieval coinage due to age, forgeries and the rarity of gold and silver coins, which would also apply for most other nations if they existed when precious metal coinage was struck for circulation. 
 

Even if you excluded precious metal coins you’ll still need to be patient and have a deep wallet to even make a dent in some countries. 

In my experience Afghanistan is a tough one to complete from the mid 20th century. Their 3 newest circulation coins can be found allover auction sites but some of their 70s and 80s coins elude me. I've found non circulating commemoratives from Afghanistan before completing any circulation set before the millennium.