Part of greed is lack of discipline and bad decision making.
Lack of discipline contributes to greed by making it harder for us to see it's a bad idea to keep seking more when it's not needed. When we lack that piece of information we need for making decisions, we tend to make bad decisions.
We all want more money-- those bills won't pay themselves.
After going through a few occasions where we lose money, we should know enough to see signs when it's better to quit while we are ahead. We may still get burned financially, but it won't be because we made bad decisions.