You were talking about European countries. Perhaps you have a vague idea of what Europe looks like, but if Germany invaded the Netherlands, there would be no Western mujahideens pouring in from Belgium (also, since when was the population of Iraq and Afghanistan devoid of military training, which was my condition?), nor would Germany have any trouble maintaining presence in a country which it borders with and which isn't half a globe away and sporting a completely different culture nor would there be any significant asymmetric warfare since the Dutch don't have a kalashnikov in every family nor do they possess an inhospitable landscape suitable to resistance apart from the urban warfare, Grozny-style (which means quite a bloodshed). Furthermore, I would like to see a European country without army with no allies - e.g. the Baltic states lacking air force are paying for aerial defense from other countries. If you had no army, you would still need to pay for defense, either by cash or by less tangible means, which is incidentally how the smallest members of NATO enjoy the stay in NATO or how Andorra and Liechtenstein can feel safe. Of course, you can try leeching on others, primarily hoping for American goodwill for instance but that is not the smartest nor safest solution.
Essentially, you are daydreaming about armyless Europe (and other regions but I don't comment on those) while your examples only work in distant, underdeveloped regions. Even then, by mentioning Africa, you are pretty much shooting yourself in the leg. Those countries have armies and that's why those wars are not decisively ended and the underdog can fight on. Did Ethiopia managed to reannex Eritrea? That question is rhetorical, despite the enormous manpower difference.
The fleeing Iraqis set those wells on fire and some of them burned for as much as 10 months.