Gatbsy almost breaks a clock.
Gatsby knocks the clock off the mantle when he is pretending that he is calm. In fact, he does not feel calm. Actually, the clock is a metaphor.
Luckily the clock took this moment to tilt dangerously at the pressure of his head, whereupon he turned and caught it with trembling fingers, and set it back in place. Then he sat down, rigidly, his elbow on the arm of the sofa and his chin in his hand. (Ch. 5)
The clock incident shows many things. It shows that Gatsby does not feel comfortable around Daisy. It also gives Daisy a chance to comment about time.
“We haven’t met for many years,” said Daisy, her voice as matter-of-fact as it could ever be.
“Five years next November.” (Ch. 5)
Daisy acknowledges the reality of the situation.
Nick comments that it seems as if the clock actually did smash. The clock is a comment about perception versus reality. It is described as “defunct.” It no longer works, just like Daisy and Gatsby. It is only for show, and is pretending to be functional. Its ornamental nature fits Gatsby to a “T.” When Gatsby knocks it down, its sham is revealed, and so is his. Their relationship cannot be real. Gatsby cannot be real. He is farcical.
There is also the time element here. Clocks are a perfect symbol for time, of course. When Gatsby knocks off a non-working clock, it is an acknowledgement that time stopped for him with regard to Daisy. Gatsby lives in a dream world. Nothing in his life is real. The clock is Fitzgerald’s way of reminding him, Daisy, Nick, and the reader. Nick sees things as they are, and sees the fantasy too. He sees it fall apart. Gatsby, however, does not acknowledge it. He apologizes about the clock. He does not see that it is not working, and not real. He does not see its falsehood, because for him the fantasy is what he always holds onto.
The moment in which you are describing is when Jay Gatsby, later identified as Jay Gatz, almost breaks an antique clock in the home of the narrator Nick Carraway. This is the first scene that we see Gatsby in a most vulnerable state. He is extremely nervous and his usual calm cool exterior is shattered in the presence of Daisy, the woman that has been his obsession for the past 5 years.
At this point, Gatsby has planned to reunite with Daisy; an act that fulfills his desire for her to finally see the success that he has created out of his life. The meeting place is Nick's home which is directly beside Gatsby's palatial mansion, a mere stone's throw away. Gatsby's nerves have gotten the best of him and leads to inattention causing him to knock over the clock.
The fact that Fitzgerald uses the clock as the item which almost shatters in that particular moment can be tied many factors. The shattered clock symbolizes that the hours leading up to the reunion is now over. The clock, an antique broken item, is like Tom. The ever present reality of the "old" versus "new"; despite Gatsby's hope of ignoring the realities that the old presents the status quo remains. Gatsby will always stand in the shadow of the ever present antique clock.
When Gatsby meets Daisy he ends up almost knocking over the clock in Nick's house. With this simple thing we see a small break in Gatsby's free going, calm exterior. For the first time we see Gatsby nervous and actually reacting towards something. With the falling of the clock it leaves room for so many interpretations to the reader. It could mean that perhaps time has stopped for the two and they're stuck back when they were lover birds or it could mean that Gatsby's time is up.