Back when I was 18 and still knew everything, I went to the local casino to give this a try. In two hours I turned $50 into $550.
Towards the end I distinctly remember looking down at the spinning roulette wheel, and looking at the $200 bet I had just placed on red, and thinking "what the hell am I doing...?" That $200 represented well over a week's income for me at the time.
But sometimes we get lucky - red came up, the bet was paid, and I took my winnings (including $100 in chips still in my pocket) of $500 profit, and left.
How often do I play roulette (or gamble) now? Never. I was a stupid kid who got lucky. The system helped, but it could just as easily have gone the other way. Regardless of the events that went before, that roulette spin could have come up black, or even green (the zero), meaning I had less than 50% chance of pulling it off.
I guess sometimes we learn from good experiences too.