Answer:
The attack on Pearl Harbor had failed to completely destroy the Pacific Fleet. The Japanese bombers missed oil tanks, ammunition depots, and repair facilities, and there was no US aircraft carrier present during the attack. This failure came back to haunt the Japanese in June 1942, when US forces won a major victory in the Battle of Midway, decisively turning the tide of the Pacific war.
When the Japanese started plotting to attack Pearl Harbor on purpose, it was morally wrong and, some would argue, cowardly. Japan's attack on Pearl Harbor was a stab in the back to the United States, but it only awoke a sleeping giant.