Most of the time, greed really push you to change the direction of your plans, there are position which you already reached your target but instead of stopping you choose to keep trying to earn more, and in time that the direction of the market turns against you, that's the time that you really regret why you choose to stay instead of quitting and withdraw the money that you supposed to earn.
Exactly, greed also can make you not to accept the initial profit that you must have already earned. Greed can make the trader to overstay in a position that they are supposed to have exited and take profit first profit but because they are expecting a huge profit, they will not exit the trade until they lose the first profit. Greed can make the trade to use a big lot size or a leverage size.