Two world wars were being fought due to a minority complex called nationalism
For centuries the German states which more or less united under Bismarck in the first German unification in 1871 had been left to be played around with by the other major players in Europe, namely France, England and the Holy Roman Empire under the Habsburg families. Most of these micro states did not even go beyond a field or a pond and were the victims of many wars and intrigues being fought by the many courts which existed back in the day. Their dukes, kings and barons where under constant thread to be either swallowed by a coalition of their neighbours who wanted a piece of their pie or aligning with the wrong of the three big players which was at the losing end of one of the wars they fought depending on which century it was. In addition their most beautiful and richest princesses were being married of to the current day Windsors, making them so German that they actually had to change their name when being German went out of fashion in 1917.(well that might be a bit over the top, but you'll get the point) The only thing they had in common was that they were not Muslims, but that is a can of worms i do nit want to open for this piece except to mention the crusades at least once.
The first opportunity for nationalism on a bigger scale, which became popular not only in Germany at the turn of the 20th century, presented itself to the Germans when they got their own country in 1871. Even this state only evolved because the Prussians undermined the remaining German mini states with their military power after the Franco Prussian War. So even the unification of Germany meant that some local barons and dukes, especially in the south of Germany, lost power and influence by being simply overpowered by military means.(makes you think of Russia 1945 - 89 and present day America, doesn't it?).
So we have a country in the middle of europe which experienced rape and pillage for centuries on their turf (literally) by their neighbours, because their armies had to march right through their territory to attack whoever have might insulted them due to other beliefs, having resources they lack or more beautiful women.(back in those days women were a commodity and would fall under the category of resources; yes nasty thing to say, i know, never the less it makes it not untrue). Luther and his Reformation also did not necessarily help this dynamic. This new state only is in its very existence because of the military strength of one of it parts, yet is still aware that most of the surrounding countries have more money to spent (England's colonies), a longer history of succesful warfare on land (France), a bigger and better navy (England) and more people to spare in case of war (Russia). Meanwhile these European countries compete in shouting how they are the latest and greatest putting emphasis on what makes them different rather than what they have in common. What will you do if you are the weakest and youngest of the bunch ?
You will go to the gym and train hard like a teenager with a minority complex who is too short for his age and does not have a beard yet while there is a lot of emphasis being put on beards for people in senior roles in your society (coincidence??). You will use steroids (pure blood), clang and bang the iron (our tanks must be bigger, our ships too) and blame your shortcomings on everyone around you rather than yourself. Once you have built the muscles you will want to flex them, especially when feeling threatened by others. Completely overestimating your own abilities you will challenge everyone of the more experienced elders around you. As your outbursts come rather unexpected it will take your parents (you could think of the allies who won at Waterloo as the parents of the german state. They welcomed a new buffer state in the region who would and could keep France at bay) rather long to realize how bad the situation is until it is it is too late and you have just impregnated Europe with war. The brutality and swiftness of your actions is shocking to those around you, as you feel treated unjust and not have the experience to understand the full reach of your actions, yet.
So Germany did behave like a careless teenager with a minority complex and if an austrian dwarf with a joke of a moustache, pumped up by hatred and propaganda, inventing a hideous salute which makes people seem taller than they are and click their heels in obedience is not the very personification of a minority complex, I do not know what is.
In some sense the fear of the Germans to be carved up again was justified, because that was the first thing the allies did after the second world war (admittedly with a great deal of justification). They carved Germany into parts again and it stayed like that until 1989.
It is sad and disturbing that it had to come to the two world wars to end on a serious note, which i think you should with this topic.I think nationalism was at the root of these conflicts, because it breeds militarism. The EU is an attempt at federalism to create peace and less deaths and that is why I think the spirit of Helmut Kohl should be continued, who was a major driver behind the EU.The nationalism bred by ideas like Thatcherism will have it consequences in the long run. Currently nationalism is on the rise again in Europe partly based on animosities against Germany. Hereby you will find a good reminder of why we should all take care, especially if you are a German (and I am), that this will never happen again. That was a lot of isms in one pargraph. Stated in simple language:
Peace is only achieved when emphasizing what we have in common and what we will lose in conflict rather than pointing out what makes us different and what is rightfully ours for the time being. Here is a reminder worth every of the 18 minutes:
If you want to know more about Germany I recommend that you read Germania by Simon Winder to get a entertaining, at times a bit too british overview of Germany as a start which gave me some of the ideas for this article.