俾斯麦：美因茨你的咖啡真难喝！ 美因茨：← ←

陈年老梗拿出来晒晒太阳。
不过为了故事好编，改成了加不加糖.
其实做这个时候还突然开了个脑洞，抓住了皇家的人怎么办，当然是灌她一壶铁血的咖啡了2333
（顺带一提这个故事的小设定是除了指挥官和俾斯麦喝不了美因茨的咖啡，别人都能喝233）

the story is simple
The main point is that the commander and Bismarck are not used to drinking sugar-free coffee.（In fact, there was no mention of sugar-free coffee.As for sugar-free, it is for later editing）
There are actually two sources of this.
1、
Mainz in the game has some special craze for coffee. She loves coffee so much and it's sugar-free, she thinks adding something is blasphemous.
2、
There is a voice dialogue in the game Company of Heroes that says that coffee is hard to drink. And in order to refer to Germany, the natural name is Hans.So with Hans your coffee sucks.

So this little story is an extension of that.