I assume that people come to the gambling industry as inexperienced people. And in the process of their activities, they gradually learn from their mistakes. Unfortunately, some of these mistakes are dramatic and cause us quite serious psychological trauma. As a rule, this is due to gross errors and stupid persistent beliefs that push us to the edge of the financial abyss.
First of all, this is risk management and money management. The second is probably unsystematic play. Let me make a reservation that I do not mean casinos, as well as people playing "for fun". I mean sports betting.
So, how much did your mistakes cost? Did they cause you a serious psychological blow? What were your mistakes, did you learn from these mistakes and do you apply this knowledge in practice now? Were these mistakes simply painful, dramatic or catastrophic?
Depends on what you consider a "mistake". If you bet with a sum of money you cannot afford to lose and then lose the bet, would that be a mistake? You made the decision consciously after all... A mistake is putting in the wrong number and accidently betting too much money and losing. I prepare myself for any loss beforehand, so while it does feel disappointing, I would not bet such a high amount that would cause me psychological trauma. That is simply foresight. I think any adult should have a basic foresight. At least enough not to cause themselves trauma.
I think affirming peoples bad betting decisions as "errors" or "mistakes" is only going to enable them to continue making such "mistakes" in the future, since they won't see it as their fault or accept any responsibility.
That being said, my biggest mistake is betting on a game which had rules I was unfamiliar with, thinking that I had already knew the rules. Which could perhaps be considered a legitimate mistake that cost me money.