Isn't Brazil a "First World Country"? What do you say China, isn't it a global superpower?
Never heard of park jeun gye and i don't know what else she did besides corruption. Same thing applies to that slovenian leader, but i'll do an attempt.
1. Mariano Rajoy
2. Donald Trump
3. Silvio Berlusconi
4. Viktor Orban
5. George W. Bush
6. Tony Blair
7. Tony Abbott
8. Scott Morrison
After that i don't really know. The 3 last french leaders and some uk leaders could be considered but i don't think they're top 10 worthy as of yet. But I don't know Sarkozy well enough.
Greek leaders could be considered and should be named and than add that South Korean one, whatever and that's my list.
Lol. Mariano Rajoy was not the best leader I can imagine, but he's not bad enough to be on the top of the 10 worst world leaders. In my opinion he's not even the worst of the Spanish leaders in XXI century, because José Maria Aznar was in office until 2004. Aznar was an unpleasant guy who engaged our country in the invasion of Iraq and set the foundations of the real estate bubble that broke after 2008. In what concerns Argentina, I think it's a tie between Cristina Fernández de Kirchner and the vapid incompetent Mauricio Macri (that country has bad luck with leaders). But again, if Argentina is "1st World" then include Brazil. Jair Bolsonaro is on top of the horrid rightwing populist bunch alongside Donald Trump, slightly above of Silvio Berlusconi, Viktor Orban and Benjamin Netanyahu. My beloved Aznar would be at the level of conservatives like Tony Abbott or Dubya. I am missing a lot of terrible leaders, but want to make a special mention to Tony Blair. Also. Lol at the guy who includes Pedro Sánchez or Justin Trudeau here (it's not that I regard them exceptionally good, but there is plenty of first quality stuff to contest Mr Horrid Leader of the Century)