have you played in this kind of underground gambling den before?
No, because underground gambling has no regulations and you will get scammed 100% of the time. And maybe worse, robbed or kidnapped.
Underground gambling is glorified in movies and shows but the reality is you are surrounding yourself with shady figures who are trying to get your money from you while making it look like you are indulging yourself in regular gambling activities.
It is best to stick to regulated, legal casinos.
The cops could raid at any moment, mobs certainly gaslight people and look for a way out. All that fast actions causes anxiety. I've never gone there but I intuitively see it like in the movie. A place for tough guys that wouldn't hesitate, at the slighest promo, to ignite chaos. However, the tension is always high and losses is mostly high too at that state of mind. The brain feels better when we are safe, gambling while considering negative events very close to the vicinity drops down the senses of gambling by alot.