In my opinion gambling becomes addiction because of if i have been losing it make me curious and that is make me addiction of gambling.
This is true as some people like to try out different strategies to see if they can win against the house edge. The joy is not in winning but in figuring out the different methods and trying them out.
making good success with the way you intended to be is really an exciting part of gmbling and by making it over and over you are being addicted and you keep wanting to win more and more or lose in the other way.