Greed has a major part of affecting those who enter gambling with a right mindset, except it is well controlled. some players claim they are playing for fun and when they make a little win, they become so excited and start playing more because they intend to win more and with time they would forget all the set rules and regulations of the game. Anyone who is does not have self control will have problems with gambling, better to work on this.
Gambling is a game of fun and whatever fun that is done without control can also lead to addiction, so it is possible to play for fun with all set rules and still end up addicted if not controlled. For me I play for fun and I set limit when playing and irrespective of how the game might unfold, I dont exceed my limit.