Let's discuss the possibility and consequences of Germany allying with Great Britain during the Imperial age.
For starters, I think there would have been a good opportunity if Germany ceded all African Colonial claims to Great Britain during the Berlin Conference. For one, this would have alleviated future upkeep for territories that did not yield their expense, as well as putting the two nations on better terms from the beginning. I'm fairly certain that if Germany was just a tad bit more cautious, they could pull off an alliance.