Stu Ungar
The basic reason for why Mr. Ungar changed from gin rummy to poker was that he was a tiny bit too good at it. So skilled in fact, that no player possibly could stand up to him. Even the commonly called champions who were supposed to be the best at gin rummy were decimated when they played against Mr. Ungar. One of these gin rummy professionals was Harry Stein, nicknamed, "Yonkie". Harry Stein was handed such a belittling blow at the hands of Stu Ungar that he evidently quit participating in it as a pro and never resurfaced at a gin rummy tournament.
Accordingly, with a reputation like that it was not too long before gamblers became shy of betting against Stu Ungar. He could not find any games and in his agony he began doing something no one had performed prior. He offered beginning handicaps to likely competitors in the hope that they might play against him if they thought they had an edge. He deliberately played from a bad position and one tale has it that stu even competed against a consistent absconder. Mid game, he received a few words of wisdom that the bad egg was at it once more but Stu Ungar stated that he deduced of the dishonestly and he would still come away with a win, which he did, of course.
The same problem followed Stu Ungar to sin city. He won so often that the poker rooms started requesting that he not to compete on their poker rooms anymore. The reason for it was that other casino players refused to be seated at the poker table if he were seated.
Stu Ungar is recollected more for his accomplishments in texas holdem poker but he himself always said that he was a whole lot better at gin rummy.
He beat Doyle Brunson in the World Series of Poker in 1980 to become the youngest world camp. Due to his looks that made him seem far younger than he was, he got the nickname, "The Kid".