Wasn’t Germany a biggest British ally till WW 1? German mercenaries fought with the British against ‘Murican revolutionaries.
Germany and England was allied up until the late 1890's. Germany was a new European and world superpower as all the German states unified in 1871 after the Prussians and other German states humiliated France in the war in 1870 and declared their new empire in the Versailles palace.
Germany wanted "a place in the sun" as they believed it was their right to be seen as a big power. So they sought out to gain a big colonial empire and also got African colonies in Cameroun, Togo, German South West Africa, (todays Namibia), German East Africa (todays Tanzania).
Problem was the British and French were scared shitless from this new superpower who had by far the largest army in continental Europe together with the second biggest fleet. This last thing triggered the English big time as they always wanted to dominate the high seas so the Germans wanting to have a big navy started an arms race and meant the British sought alliances with France and Russia instead.
Not to forget the British always wanted to oppose the strongest power on the continent, that's why they had so many wars against France. Now Germany was slowly becoming the new enemy.
Not to forget Europe was very patriotic and nationalistic back then. What the Germans wanted (empire and colonies), wasn't wrong at the time because the other big powers had this same thing going for many years - difference is now there was a new boy in class.
Kaiser Wilhelm should never have backed the weak Austrian-Hungarians, maybe then WW1 could've been avoided.
Long post I know but the German-English relationship is complex from a historical point of view.