I've often heard Europe described as a 'powder keg' spoiling for a reason to go to war in the period leading up to the assassination of Franz Ferdinand. But there's usually not much elaboration other then that. What was the reason for the powder keg? Was it excessive nationalism, a false sense that each side would be the winning side, a belief that the home team had superior technology, excessive idealism, or something else?

What did each side feel they had to gain by going to war, or loose by not participating? I realize the answers are complicated, and still debated but I'm interested in a general overview of the zeitgeist of the time, if possible. Thanks