Imagine someone offering you a sample of a new kind of candy, and when you try it, it's the most uniquely delicious thing you have ever tasted. Then, they ask you if you'd like to buy some by the box.
You take ten.
After some time has passed, you suddenly find yourself without candy. You return to where you bought it, but the person who sold it to you has vanished, and in their place, a small sign. Its ornate lettering reads "Out of stock. Be back whenever."
Saddened, you return to your residence, and rumage through the empty candy boxes. You find one with a few crumbs in it, promptly eat them, and then sit down on the floor. Shedding a few tears, you hold the box close to you, close your eyes, and imagine the day that you'd find that person again, and buy their candy.