The Green Light in The Great Gatsby holds so much symbolism. Gatsby being seperated from this green light,where Daisy lives, by the ocean makes it difficult for him in his heart. It represents his longing to be with her. Her being so far away across the sea makes it almost impossible for him to get to her. "In our first acquaintance with the light, we see Gatsby reaching for it, almost, in a way, worsipping it" (https://www.msu.edu/~millettf/gatsby.html) Gatsby has almost idolized this green light because everytime he looks at it, he thinks of Daisy and how much he wants to be with her again.
Another interesting factor about the green light, is the fact that it is green. Green represents go, speed up, or move farward. That of which Gatsby compelled to do, but unfortunately he cannot. As much as he wants to go forward and get to her, he is being restricted by the ocean layed out infront of him.
Finally, the green light represents how Gatsby is never satisfied. He's always wanting something more. Sometimes things he can't have. He doesn't know how to be happy with all the wealth that he has. While a huge party was going on at his house, instead of enjoying himself and being satisfied with all the riches he has, he was outside looking at the ocean, longing for Daisy. Wanting something more, something he couldn't have. "And no matter how much he has he never feels complete" (http://www.homework-online.com/tgg/symbolLight.html) Gatsby could have everything in the world he could possibly ever ask for, but that would never be enough.