I personally do not play slots, but do you think that is why people like slot machines? Short of breaking their code?
If you do play, you will understand.
There's no breaking a code or something unusual here. These people know that it's hard to beat a casino game but the adrenaline is always there so it builds thinking on their brain that they can challenge the casino.
I'm sure those guys already experience winning a good amount. That's one of the reasons why gamblers continue to play because they actually feel the experience of winning a good amount and they want to feel the same experience again and again.