"Take what you want," said God, "but pay for it."
Everything in life has a price, checks, and balances. Most people don't consider the prices they must pay for a thing, and just go merrily along, ending up lamenting whatever hurts or losses they suffer later. You have to learn to decide, consciously, if you're willing to pay the price that some moment of joy might bring you. You have to be willing to say to yourself, "In the end this may hurt, but the good I get now is worth that." You must learn to ask, "Is it worth it?"; and you must be willing to pay the price.