Oh good grief. Wars are almost always fought over resources of some kind, as well as (closely related) trade and power and influence.

1) ISIS is an unforeseen by-product of Bush's Iraq war (and incompetence).
1a) Bush's Iraq war is still a bit recent for us to know the real reasons; there's charges of it being due to Saddam trading Iraqi oil for Euros instead of Dollars, which weakens US hegemony and the power of the petrodollar as the global reserve currency. Even if this wasn't the real cause, setting up a US-friendly regime in a country with significant oil resources is obviously attractive to globalists in the US.
1b) Afghanistan has no oil, but it has significant mineral resources. It also has a strategic location, which is exactly why the Soviets invaded, because they wanted to build a pipeline through it.

2) Vietnam was a proxy war about hegemony. The USA and USSR were fighting a cold war to gain more power globally. Vietnam is next door to China; the US wanted to stop the spread of USSR-friendly (and Maoist-friendly) regimes, and push for US-friendly regimes.

3) Korea was much the same as Vietnam. Also, our new ally Japan is right next door. By defeating Japan and setting up a friendly government there, we now had a strong presence in that region which we wanted to protect. By the 50s, Japan was already a significant and growing trade partner.

4) Japan and Hitler weren't ideology, they were about power and control and resources. Why do you think Hitler invaded the rest of Europe? It wasn't to exterminate people (though some people in his administration took the opportunity to do that, plus that was a convenient way to steal their wealth as Jews tended to be richer), it was to gain control of all the land and resources around them. Go read about "Lebensraum": the Germans had dreams of conquering everything around them, eliminating or enslaving all the people living there, and then colonizing those lands themselves. They thought that before long, they'd have Germans living in the Ukraine or wherever, with each family having several Slavic slaves. The Japanese wanted to take control over the Pacific Rim, just like the Chinese are doing right now to an extent (though, like Germany, Japan wanted to do it the old-fashioned way where you set up an empire by invading the other countries and occupying them and turning their occupants into slaves or people of limited rights).

5) WWI was all about resources: it was a massive land-grab by all the European powers. They all wanted to take over their neighbors and grow their borders and establish control. The US should have just stayed out of it; none of the Europeans were in the right there, except probably the small countries that got bowled over like Belgium.

The American Revolution was about power and money: the colonial aristocrats wanted more power and lower taxes for themselves, and the British government didn't want to give it up because the whole reason you have colonies in the first place is so that the mother country can exploit the resources of the colonial lands. The Civil War was over trade and resources: the agricultural resources of the South were too valuable to allow to secede. Gulf War I was over oil and hegemony: the US didn't want Saddam having too much power in that oil-rich region. The French Revolution (as I understand it) mainly was a class war: the lower classes were sick of the upper classes screwing them over (which is also about resources; in a society where the elites have too much power, they also control all the resources and wealth) so they stuck them all in the guillotine.

Wars are not about ideology; they only appear to be because the ideology is inseparably intertwined in the competing nations' leadership, and allies tend to have similar ideologies (e.g. US and Australian and UK ideology are very similar and compatible, however these nations also have historical and ethnic reasons for being allies, which also led to them having similar ideologies).