Most widely hated countries on earth

[Middle-aged Europe]

Depends on the region, I guess.

America and Israel are obviously more hated in the Arab world than in Europe, for instance.

If we go by the traditional "most trustworthy partner" question in German opinion polling, China is currently the country that is viewed with the greatest "suspicion" in Germany, closely followed by Russia.
France usually tends to win here, followed by the UK and/or - at the moment - America. The United States tends to oscillate between extremes pretty hard here, depending on who is President at any given moment (that seems to be a phenomenon that started with Dubya though since his father was fairly popular around here).

Personally I try to not hate countries, but governments. Of course some governments have existed for so long that it is hard not to conflate the two. I guess North Korea has no legitimate reason the exist as a country outside of its role as a personal fiefdom for the Kim family, so one could say that I "hate" North Korea.