That's true, many of us thinks that way. We tend to think that if we are going to try it again we can have a chance to win again and again for sometime but the result is opposing to what we think. And the cycle on how we think that way keeps on repeating and moving, that's why we still gamble even we keep on losing.
So, basically that confidence is because they are too addicted and think everytime that the bankroll was low. But don't know seriously when these guys will learn that its the house edge that cause them loss.
It's very true. The gamblers never see that they lost because they didn't have luck, but because they made a mistake, like having a low bankroll or to don't change the game strategy in the right time, to don't increase, decrease the bet amount, etc.
And all because they are too addicted and committed in defeat the house edge and make profit.