I believe from dice and roulette games we can get maximum rewards when compared to casino and sport betting,I didn't made any big amount which is considered to be as maximum reward in single bet but when I calculate the average most winning rewards the it will be the sport betting I think.
Well, I guess you could just estimate how much you have won in something, that's not going to stop you in my opinion. Probably, you don't remember it because it wasn't that much of a win to you because of the prize you won. I guess you are really lucky choosing the teams who win or lose. That's a great skill.
Not too great to be honest because I hardly go for betting on sports because of the match fixing in recent days but I can predict most of the games because I closely watch the previous games and analyze very deep that who can be a winner but still we need luck to win those games.