While trading we have to follow few rules and without following those rules there is no way to be a successful one except a successful by chance. There are lots of rules of them greedy plays a vital role. While trading never be greedy. If you become greedy while trading then you can be assured that there is 90% possibility to be a lessor.
Most of the times greed can lead to major losses in your portfolio except when your luck favours you. I've had some experiences when I acted greedily and incurred some huge losses so now I've learnt my lesson and now I don't act greedily. As the saying goes, "There is no greater calamity than being consumed by greed."