Having greed is good, its the stupid mistakes that make you lose money. Greed is wanting more money, holding more than you should is not "greed", its a mistake, if you know what you are doing then you would sell at the top and buy at the bottom and make more money aka be greedy.
there is a way of greed to use as goodness while there are more to losing , if you are a Bitcoin investor or those ranking coins then yes you can rely in Holding and having greed in thoughts but if in Shitcoin? then you are a loser completely.
So all in all, do not make all the mistakes confused with each other, because emotions in trading world is very dangerous and mistaking which emotion is which could be even worse and that's an important thing.
emotion must not be in trading time because this will add more losing when you decide feeling bad or over happy.