Gambling is all about our decision, we can decide to gamble and we can decide not to, it's all about what we want and when we want it, this I believe is not so hard.
But then, if we ever get to a stage where we actually don't want to gamble but we still can't hold ourself back from doing it, then it simply mean we have become addicted to gambling, if actually there is no other trustable way to find out when and if we are addicted to gambling, then being unable to stop oneself from gambling even when in their mind, they really don't feel like doing it, then, that is a good way for such a person to know that he or she have become addicted to gambling, or he or she is getting addicted to little by little.
So, for a gambler monitoring him or herself in other not to get addicted to gambling, the above is one of the symptoms to look out for, and when such is noticed, it's time for the gambler to draw him or herself back by reducing their gambling activities.
I agree with you on that, our inability to control the desire to gamble more is the core addictions that we are talking about, some time it good to check yourself and see if you are actually gambling right because once there is the inability to control your gambling excesses it becomes bad for the whole community since gambling addictions and it impacts rob on all and not just one person. That is why is better to have an established pattern of play while gambling so as not over-dependent on it to the point that it could become an addiction.