I guess I will sometimes bet like this. Let's say I go to a casino and then double my money. I don't just walk away, what I will do is take my principle and then pocket that. I will then gamble the rest of the evening with whatever I have left above my cost basis, which sometimes I lose all of, but other times I end up doubling or tripling, just depending on the situation.
Doubling your capital is getting x2 of it mathematically that's a hundred percent Profit, most people don't realize how huge it is to get 100 percent of your capital...your strategy of using your profit to play is very wise but 70 percent times those Profit will be lost, it's better to double your stake and just leave it, that's a very hard thing to do cause it requires a lot of discipline.. trying to triple or make it x4 might just make you lose everything, I've had experiences were I was supposed to stick to doubling my take but instead I chose to make it x5, I lost a lot due to this.
Yes and the core of the trigger of the problem is always about greed, as you said that successfully getting a 100% profit is a very good result and it is a rare situation, but unfortunately, often gamblers who have succeeded in winning actually continue the game with the hope of getting a much bigger win, or x10 of the capital.
Actually, all decisions are within ourselves, and if we cannot stop the desire to continue to double it, then the game session will never end, because greed will definitely continue to grow, such as even though you have succeeded in doubling your capital x10, but surely in the end you will assume again to increase it to x20 and in the end all of that will end in losing everything and regret dominates.
So the point is when you have reached x2 of your capital for example, then it is clear that it is the right time to cash out, winning is much better than losing.