The first of the two which I am sure most know what I am talking about is money. 
No human will ever say, I have enough money now, maybe I should try to stop making any more. We know that will never happen. The more money we make the more we want to make even more. Most of us would say I wish I have a million dollar, I will be so happy, but as soon as we make that million you will find us making plans as how to grow that million into ten or even twenty million dollar.
The second thing that humans can never get enough of is knowledge. No one knows everything. Even the most genius people still learn different things every day. The longer you live the more you will know. Humans’ search for knowledge is endless, and that is what makes life interesting. If humans did not have that hunger for knowledge and exploration life would be boring to many of us if not all. From the day a human is born he or she start learning and they keep doing so until they leave this life.
As far as I am concerned, I believe I am no different from any other human. At this stage of my life I am one of the many saying I will be more than happy to get a million dollar, but I am sure that will probably change as soon as I achieve that goal. When it comes to knowledge I know I have learned a lot throughout my life, but I am sure what I know is nothing but a drop in an ocean of what’s out there to know.
Finally I would like to say that there is nothing wrong with being eager to make more money or to have more knowledge. What matters is how you spend that money and how how you use that knowledge. Good people tend to help the needy when they know they have more money than they need. While smart people who are good use their knowledge to invent useful things that would help humans and ease the suffering of the unfortunate ones.