These were the incidents that precipitated war - but these specific incidents underlined the larger strategic picture: that Germany had zero respect for the USA and was prepared to act with extreme aggression toward American interests without a second thought. This is why Wilson wanted to do anything he could to avoid confronting a victorious Germany down the road. He could theoretically have kowtowed to Germany instead.
I wonder what would have happened if the Kaiser had won WW1. No Nazis in Germany would be a good guess. Also possibly no Bolsheviks taking power in Russia?