on what does owl-Eye blames the accident after Gatsby's party? What is ironic about his claim?

At about two in the morning, Nick decides to walk home; on the way, he sees Owl Eyes, who has crashed his car into a ditch. Owl Eyes loudly proclaims that he is finished with the whole business; it is not clear (either to Nick or to the reader) what, if anything, he means by this. Owl man claims he wasn't even the one driving. This might be ironic in that Owl man is very much a part of this business, whatever he means by it. Check out this GradeSaver link,

http://www.gradesaver.com/the-great-gatsby/study-guide/section3/