Catastrophic events are key in the Great Gatsby.  The war from which Gatsby and Nick survives was a catastrophe that was averted and the course of the story would have been very different if Gatsby or Nick had died while fighting in Europe.  Another catastrophe is the one where owl eyes crashes his car and the wheel is removed.  This catastrophe was a minor one that didn't really affect the course of the story.  There were catastrophes that were not so minor and had a major effect on the course of this story, one such problem is the one where Daisy hits Myrtle with Gatsby's car.  If the car which had hit Myrtle was someone's other than Gatsby, George would not have shot him.  Daisy had a hand in other catastrophes as well.  Her affair with Gatsby was a major catastrophe that resulted in Tom and Daisy leaving the East and going back to Chicago as well as the death of Gatsby.  Her affair with Gatsby resulted with his death because it angered Tom and he told Wilson that Gatsby had hit Myrtle.