The worst thing a player can do is chase their losses and try to recover with more money or a deposit, I think that this is the first symptom of an addiction, however a person who is responsible enough will know that when this type of Things have to stop so as not to make more mistakes, this is the first thing to do, in case you don't know , you are running the risk of continuing to spend money in vain, because I don't think you are going to recover what you lost, that is like swimming against the tide, for that the best thing is resignation and spend only the money that you have Destined to lose.
I disagree that chasing losses is the first symptom of an addiction but I believe it can trigger the gambling addiction. At first a player will give himself a reason to gambling and that is to recover losses then eventually gambler will be lost and just gamble and don't mind if they will recover losses or win a huge amount, all they care is that they have to gamble to suffice their uncontrol urge to engage in gambling activity. Responsible gambler may chase their losses but will stop if they feel that their attempt to recover the losses is going nowhere. So they will stop even before they suffer a bigger losses.