For 33 years I travelled, lived and worked all over the world.
That's a long time, and a lot of countries.
I can truthfully say that I never once tired of my job or the travelling.
Here is a list of countries I have either NOT visited or have no memory of ever visiting. (probably there are more):-
North America
Greenland
Belize
Guatemala
South America
Paraguay
Uruguay
Africa
Eritrea
Togo
Chad
Congo
Asia
North Korea
Laos
Bhutan
Middle East
Afghanistan
Turkmenistan
Uzbekistan
Kyrgystan
Tajikstan
Europe
Georgia
Armenia
Azerbaijan
Moldova
Belarus
I haven't been to hardly any of the islands of Micronesia, Melanesia and Polynesia (Oceana) except for Fiji and Guam.
On plenty of my long haul trips I would purchase a 'round-the-world' air ticket as it was often cheaper to do that. Anyway, travelling in that way and taking some holidays I was able to visit many places that my business would not normally include.