A responsible gambler is a person that knows when to stop and knows when to quit for the day. You will see some people gambling and when they lose for that day, they don't stress over it, they just close for that day even if the objective was to make money, they don't over do gambling like it's a do or die affair, it's strictly based on their on rules no matter the outcome.
I do not believe this defines a responsible gambler. What if, by the time he stops or quits for the day, he has already exhausted himself, possibly more than is necessary? I have taken the time to observe gamblers and their behavior.
Some gamblers do not panic no matter how much money they have lost, and these are the people we mistake for responsible gamblers because they do not display aggression outwardly, but deep down they regret gambling more than they can afford to lose.
In my opinion, a gambler can only be responsible if he spends only 5% of his income on gambling.