Short (futures)
To short futures contracts, brings with it an obligation to deliver in the future, to sell before you buy.
People who short futures contracts may not be selling something that they do not own yet. They may be selling something that is not even planted yet. In fact a farmer may have to pre-sell his crop to get the funds for seed. With futures there is no borrowing of any securities like with stocks. The clearinghouse only as a good faith deposit, holds margin. There is no interest or dividends to be paid. There is no deterioration of your capital because of time, as there may be with options. When there is no fluctuation in price it does not cost anything to maintain a short futures position. New contracts are only created out of open interest increasing transactions, involving a new seller and a new buyer.
Spread traders do not necessarily hope that prices fall. They may in fact own actuals in greater number than the short position. As when a rancher pre-sells part of his herd by shorting futures. Spread traders may be depending on their shorts to continue going up, just at a slower rate than the long side of the spread. The short side may be just to minimize drawdowns, reduce margin requirements and increase return on margin. The short side may not be expected to move at all, which is quite common.