Well, most gamblers I've come across In my life do the direct opposite, when luck hits them and they win a substantial amount, that is when they start gambling even the more, now, they increase the betting amount hopes that winning even more money if the luck hits again, and before they probably know whats going on, they have lost everything and back to square one again..
Taking a break from gambling after winning a good amount does not mean such one will not lose when he or she comes back, but this will prevent you from playing the wrong games and betting unnecessarily out of excitement.
They do this because it's too exciting to win. They get addicted to the sensation felt when making profit from gambling, so they want more and more and it seems it's never enough, because each new pleasure they have, the next one has to be bigger and more intense, otherwise they simply get used to that and don't feel rewarded anymore on the same intensity, so they keep increasing the bet sizes to maximize the pleasure received.
Inevitably they enter a dangerous zone where huge losses become a real threat. If they don't revert the situation soon, that is, to stop risking too much money in short time intervails or single bets, they will feel the remorse once the results stop coming on their favour.