Greed is addictive and a lot of greedy people are unable to stop even though they manage to get plenty and so is gambling and the people that regularly gamble. It's so addicting because you're greedy to win or regain your lost money and in the process you lose control of yourself and get addicted.
Because those people already had a chance of winning on any gambling game that they play. And they keep on playing looking for the chance that it will give them satisfaction plus the profit. In the end, they are not aware that it is making them addictive.
They probably notice but doesn't care, they would just go on and play and believe they can win. They have a slight chance of that happening but not always, the edge in the casino has always the upper hand.
Once they are into it they won't care anymore because they already started to do so. And they don't want to stop because when they already have losses, they will aim most of the time just for their money and recovery of it. The casino doesn't really care what will be the effect of their service to their customers, they will just think about the profit.
That's the problem, they can't control it, even if they know that in the long run, it's always the casino. Losses are inevitable but if you hit that lucky jackpot bet, then it's probably the best thing that can happen. The best thing to do is just don't gamble or don't think about the profits because you'll probably get too emotional and attached to it.