While playing it feels timeless and there are no worries.
Once the cash is gone the worries and feelings return most then say why did I do this.
Indeed, it can work as a defense mechanism. I am not an expert in psychoanalysis, but I can tell you from my experience and what I have read/discussed, we need constant higher dopamine spikes. You lose interest in other fields of life because your base level of dopamine is getting higher, and you have now become accustomed to using gambling as stimulas to get higher levels of dopamine.
In poker/sports betting, you need to focus on learning and research to get enjoyment, and your sense of achievement must come from something you have learnt through training and self-discipline. If you are in a constant delusion of getting your sense of achievement from hitting 1000x on slots believe me you will need 10000x next time, and even 100000x.
There's no such thing about contentment, because at the time that you do achieve that 1000x in slots then you will be putting up into your mind that you can be able to hit up 10000x easily and so on...
Experiencing a series of loses will be that totally wiped out on a single win or simply you will be forget and thats the reality on why gamblers do continue to play until they bust it all as long the dont be able to hit their goals then they would continue. The feel of regret will always be in the end of the line.