gamblers often lose their control and overcome by their emotion that becomes the reason why we initiate an action that was made by immidiate decision.
Some gamblers did it, especially newbies/beginners. They have weak self-control and easy to lose all funds shortly. Noted that never make any decisions based on emotion! It just endangers you and probably to end your journey on gambling too early.
The reason why gamblers becoming greedy is because they are after for taking their losses back, they always try to get it back until they lose again.
This is a common mistake and many did it repeatedly. But experienced gamblers shouldn't do this. They must know about it very well because of learning from their experiences in gambling. And smart gamblers must know that "greedy" is always ended with losses.