Everyone who watched the Lost series could appreciate the amount of symbolism that the directors have put in. However, I could never understand what was the true symbolism behind pushing the button inside the hatch? I know it looked like it was about the world ending but I believe that is still not the main idea.
One of the running themes of the show Lost was embodied in the struggle between Jack and Locke... the whole "Man of Science, Man of Faith" struggle. Locke was a believer in the unexplained and that by following signs of faith, good things would come. Jack on the other hand was a skeptic and always demanded for a reason or an explanation behind everything, almost to a fault at times.
One of the key elements of the show that highlighted this conflict was the pushing of the button every 108 minutes. The pushing of the button represented the way these two different belief types approach things that can not be explained. You could compare it to faith or religion. Many people believe in God and go to church simply because its how they were raised, like Locke who pushed the button because he believed the island had given him a purpose and Desmond had told him he had to push it. Locke thrived on having something to believe in and put his faith in. Other people might look at this as ridiculous. They insist that God can't exist because there is no proof of his existence. Like Jack who insists that pushing the button is pointless because they can't know for sure if its necessary unless they stop pushing it.
It is also interesting how the button serves as an element for each of these characters to truly question themselves and their beliefs. Jack is ultimately convinced that pushing the button is necessary and even participates in it. He realizes that even though its necessity can easily be proven, the potential consequences of finding out the truth could be disastrous (the world could end). And Locke in the end has his faith questioned and believes that the button pushing is all part of some observational study and so he sets out to stop the button pushing, even after he's built what I'll call a religion of doing so.
For more background on the pushing of the button check out Lostpedia: Pushing the Button