However, the big change came when Kaiser Wilhelm II got into power because he advocated the "Weltpolitik" which proved to be risky and dangerous instead of the Bismarckian foreign policy which was much more reliable and safe; this change came in the end of the 19th century. The change in foreign policy aimed at elevating Germany up to the ranks of the Great Powers in Europe but only antagonized her especially with Great Britain (G.B) since it challenged the Royal Navy which was unacceptable to the British and this made any diplomatic negotiations with G.B more difficult than ever.
Germany also set up a Dual Alliance with Austria-Hungary in 1879 and a Triple Alliance with Austria-Hungary and Italy in 1892 and now it seemed that if war would happen, it would be on a large scale and it would be more likely since the powers had their allies thus more daring in waging a war. Even though these causes as presented preceded 10 years before the war broke out in 1914, it is absolutely necessary to mention them as without them, it is difficult to understand why there was such a war in 1914.
In 1905, in a bold move, Kaiser Wilhelm II made very provocative move at the port of Tangier in Morocco, demanding privileges for German traders and offered help to the Moroccan Sultan against the French. However, the plan backfired as France's claim in Morocco was supported by both G.B and Russia so not only that the Kaiser antagonized himself, he got himself diplomatically isolated among the Major Powers and made a coalition between the three France, G.B and Russia possible as the Triple Entente was finally formed in 1907 as a defense against the Triple Alliance. At this point, tension had risen high and if there was any war at this point, it would have been only between these powers.
But then the attention shifted to the Balkans, a very complex region, exploding with nationalism stronger than ever. Serbia from previous war against "the sick man of Europe" - the Ottoman Empire, had gained much power and influence with threated Austria-Hungary's strategic position and her power in the region. But more importantly, Serbia was backed up by Russia which complicated the problems. In 1908, to much surprise of all nations, A-H decided to annex Bosnia-Herzegovina which angered Serbia and created much tension not only in the region but also in Europe because all powers were deeply interested in the balance of power in this region.
Before the Balkan wars 1912-1913, the Kaiser again shook Europe with his rather absurd move in Morocco, creating what now known as the Agadir Crisis in 1911. He sent a destroyer to the port offering help to the Sultan who previously asked French troops to help repressing revolts. The Kaiser's aim was to disrupt France and to gain some land there but failed again as France received support from both of her Allies now who saw Germany as a big threat in Europe and they promised French firm military aid in the event of a war. A war has definitely started under the surface already.
Then came the Balkan wars which were great successes for Serbia but then Austria feared that Serbia might be too strong and became a threat which should be "neutralized" as soon as possible. An understanding of this with the July Crisis definitely explained why there was a war which broke out in 1914. The July Crisis was mere "formality", a war has already begun at least ten years before 1914 because the tension between the powers was already at breaking point, war was certainly inevitable and it was only a matter of time that the war would breakout. Therefore the quote cited in the beginning is generally true in explaining the outbreak of WWI, however it is also necessary to take into account causes which were 10 years before the first short was fired.