In many societies, the cutting of the final sheaf of grain was indeed cause for celebration. People celebrated by making corn dolls, which represented the spirit of the grain. Sometimes these dolls were full-sized, made of the last stalks of corn to be harvested, and decorated with ribbons, streamers and even articles of clothing. Ivy was a symbol of rebirth, and so it wasn't uncommon to dress the corn doll with a headdress of ivy.
In some rural areas, the corn doll was kept in a place of honor at a farmhouse in the village, until it was time to make one the following year. At that time, the old one was ceremonially burned.
The creation of corn dolls was just one of many customs surrounding the final sheaf of the grain harvest. In Ireland, the final sheaf was gathered with great ceremony, celebrating the living things that might be living within it. If you think about it, that makes sense -- a cornfield is a perfect nesting place for small animals, such as rabbits, mice, birds, or frogs. As the reapers harvested the crop, the animals within fled, until there was only one sheaf left. Since the animal was more often than not a small, very frightened hare, the phrase "putting the hare out of the corn" came to mean the end of the reaping.
In some parts of the British Isles, young maidens were invited to cut down the final sheaf. The one who was able to do so in a single stroke of the scythe was guaranteed to be married within the year -- probably because she had just proved herself as an able and strong farmwife. In other areas, it was believed that the person to cut the final sheaf would have good luck for a year, but in other place, it was a sign of ill fortune to come.
An odd tradition in some areas was the use of the final sheaf to find the corpse of a drowning victim. The sheaf was placed in the water with a lit candle upon it, near where the person was believed to have fallen in. The sheaf drifted, and it was believed that it would come to rest where the body was submerged. It was thought that only the final sheaf had the magical ability to find these lost souls.
Regardless of how it was used, the cutting of the final sheaf meant that the grain harvest was over. Now bread baking could begin, and food stored away for the coming winter months.