It all depends on what is running in your mind at that moment after making profits. Some, might want to gamble again believing that it's their lucky moment and wants to take advantage of it.
I am sure wise gamblers will stop it when he already got winning streak. It is impossible that we are always lucky in gambling. There should be the time for losses after some wins. If we continue it with a careless way, the win may turn to be losses. So, people who understand the nature of gambling, they must stop for a while to enjoy the winning prizes.