“I did, old sport,” he said automatically,
The choice adverb ‘automatically’ reveals an awful lot about Gatsby’s motivation. He is fuelled by forces beyond his control and cannot master his attraction to the wealth and status represented by Daisy. His actions are almost non-deliberate, which invites readers' sympathies for his folly.
This idea is evidenced throughout the novel. Upon being reunited with Daisy, he is described as breaking down ‘like an overwound clock,’ reiterating the idea that he lacks control over himself.
Gatsby is also trying to get his story straight since he seems to have forgotten about telling Nick he received an inheritance.
To help improve the meaning of these lyrics, visit “The Great Gatsby (Chapter V)” by F. Scott Fitzgerald and leave a comment on the lyrics box