In what ways were th Habsburgs and the Hohenzollerns driven by similar motives?

Answer 1

In two ways: creating unity and prestige. Both Empires were made up of different nationalities and principalities, and nothing unites an Empire like having or creating a common enemy and coming out on top against it; just ask Russia's Mr. Putin.

But even in that seeming similarity there were great differences. Germany's Hohenzollerns and especially Kaiser Wilhelm II were anxious to prove themselves to the world, while Habsburg Kaiser Franz Joseph II felt secure in his place in the world. Germany's unity under the Hohenzollerns was only 40 years old at the time, but that unity was not under any serious threat. Austria's unity was a few hundred years old, but under much pressure from the many nationalities chafing under German/Austrian and Hungarian dominance.

The Habsburg Kaiser had over the decades learned the hard way that wars are always a big gamble and easily lost, so he was not at all keen on starting one. But he felt that if he let Serbia get away with backing the Crown Prince's murderers, he would undermine imperial and Austrian prestige and so only invite further internal unrest.

The Hohenzollern Kaiser Wilhelm II on the other hand was driven by a constant fear of not being taken seriously enough in the world and had only memories of Germany and Prussia winning all its wars. He thought that winning a war of his own would finally get him the position inside and outside Germany that he thought he deserved.

So although 'prestige'-considerations figured as much in his motives as they did with Franz-Joseph, the nature of those considerations was quite different. One was afraid of losing prestige, the other eager to win it.