Why did unification of Italy and Germany create difficulty in diplomatic relations in Europe (use evidence to support your argument) ?

Before the unification of Germany and Italy, the small nations that encompassed those regions all built themselves up to be powerful and developed separately. With the unification of Germany and Italy, all that very highly developed land was now under two nations instead of 20. This created a power vacuum, as those two were superpowers, and diplomacy centered around Germany and Italy.