Well, this is a really timely and an interesting question. as much as I would like to say that we are not greedy, it is our natural mechanism to become greedy specially when we know that we can take something from somewhere.
I will give below a very personal example on how we activate being greedy.You for example invested in a stock price from a low point, you have a financial advisor friend that tells you that once the price reached a certain point you should sell it already no matter if it is still increasing in stock price as it will drastically drop within the day. After sometime, it reached the price index your friend gave you, you being the optimist kept on holding on to your shares of stock as you are seeing that it it is still increasing. You did something and checked again the stock price, which to your dismay has already dropped from your buying price.
The story I told you is how most of us react specially on times that we don't listen to those who know better. When we see that we can still gain something from somewhere, we hold on to it, we demand from it. Whether you like it or not, Whether you know it or not, we are greedy in our own little ways.
You can observe it yourself that we tend to become more self centered when we have a lot to gain. Even if we know that we have enough, we still push ourselves to gaining. It is human nature - as it easier to become greedy than to give.
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