I think that after gambling for some time you somehow become "skilled" at knowing when to stop. You develop a feel about it like a 6th sense that tells you: "stop now you idiot". I dont want to call it skill tho, but it's something strange. It doesn't mean you will win more, just lose less.
True, I never felt anything like that, but I can't keep what I'm feeling. Because sometimes when I do gambling, my mind was already penetrated by greed. So it is less influential