To Tom, the most important thing is getting ahead. All he cares about is success success success--symbolized through the yellow work paper on his desk. However, as both you and I know, Tom almost dies in the play. This reveals the moral that you can work as hard as you want, earn as much money as you want, and become as famous as you want, but it doesn't matter once you die.
Another good comparison would be the play "You Can't Take It With You". This play, again, presents the idea that you can try to earn as much as you want, but in the end you can't take it with you. All you can take with you is who you actually are and perhaps the love of your loved ones--and let's be honest, if all you do is work and try to make money, it's unlikely your relationships will be strong and well-developed.