If you are gambling with money that is meant for entertainment, whether it is going out with friends to a bar, a movie or any other, even if you lose every last cent, it will not make you regret spending. But if you're gambling with money that you need for something important, like paying for utilities, a gift for a child, etc., then of course you'll regret your action when you lose it. 

Before gambling, make sure that losing this money will not do you any harm. Then everything will be great.