The many horror stories of receiving a truck load of soybeans in your front yard
are greatly exaggerated, as the longs and shorts in these situations are
resolved prior to contract expiration through the purchase of off-setting
positions.
The name of the game for a speculator is to buy low and sell higher. It doesn't
matter which is done first. If you buy first, you've entered into a "long" position.
If you've sold first, you've entered into a "short" position.
In order to enter into a futures purchase, an account has to have some degree
of "margin." This is money set aside to cover the amount that the position that
you entered into could go wrong. That's not to say that the amount of margin
couldn't change.
If a position continues to go against you, a "maintenance margin call" would be
called for to cover the increased risk that the position has exposed you to. It is
rare cases indeed that we continue with a position that has worsened by calling
for additional margin, but that's the risk that you take. And with the risk, the
rewards can come. By no means are we implying that they do, but that would
be the only reason to continue to hold a degrading position.