Giving into emotions can be dangerous, but successful is very subjective term. I would take it as being successful when we don't lose everything by playing everything we got, or even more then we budgeted. That's a win in my book. I don't necessary wait for huge profits in order to be successful. Just minimized losses. As long i am losing what i am affording to lose, i consider myself a successful gambler. That might be a low bar for someone but it keeps me straight and far from the trouble and deep end. And i consider myself greedy, not so desperately greedy i would play with a loan or anything like that. But i gamble with winnings sometimes, maybe with too greedy attitude, but that what gives me big wins sometimes. But only sometimes.
The gambler should control their emotions in the gambling,So he play the gambling without any expectation in the gambling.The biggest money making gamblers are the people who play the game without any expectations from the gambling site.Only the gamblers who doesn’t have any expectation will use their own strategies without any hesitation.Because the gambler had many options to take risk by playing without any expectation.The risk was the important one for the gamblers to make the money from the gambling site,greedy also should be avoided by the gamblers to make more money in the gambling sites in long run.
I think they will only be able to control everything, especially their emotions when they experience defeat, if they come without having a goal to produce, or what we usually call coming only to look for fun and entertainment, because if someone is more focused on winning than Concerned about the possibility of greater risks, it will clearly be very difficult to be able to take such preventive measures, expectations and hope are one of the main problems.
I think you can't just say that "they can make money if they can control themselves or without putting expectations" you have to understand that self-control and avoiding greed is only something that is useful for minimizing risk and does not mean increasing the winning percentage to bigger or more frequent, however, victory is always impossible to know when it will come because only luck can bring you results like that.