I suppose I am lucky, I never have regretted losing money at any time in my life. My Father was a seasoned Gambler and he instilled in me a Mantra that was "If you cannot afford to lose it, Don't use it!"
I am 69 years old now and never regretted losing at any time, Yes I have had bad days at the Racetrack where I couldn't pick a single winner, but if you prepare for that, Losing money is not such a bad thing. Being in control of your losses is far more important than most people realise.
Some people set aside a certain amount for Bills or Holiday's etc each Week/Month or whatever and stick to it religiously, This is a simple form of Bankroll Management Same with
gambling, You save money each Week/Month that is to be used for gambling and stick to your limits. That way you really cannot be in the hole too deep so as not to be able to dig yourself out of it.
I might have a few regrets in my Life but gambling is way down towards the bottom of the list,