Before he would take the first spoonful, my father used to pull a little rice off the top and throw it over his shoulder. 고수레, he would say, not loudly. Ants found it fairly quickly. Sometimes a bird came down for it.
As a child I could not see why good rice was being thrown away.
고수레, gosure, is what you say when you take a portion of your food and cast it out before you eat, out in a field or up a mountain. A greeting to whatever was living there before you sat down: have some.
The people who did it did not think humans were the only ones at the table. The grass, the insects, whatever cannot be seen.
You rarely hear it on a mountain now. What people do instead is press the empty box flat and put it back in the pack, and the pack is heavier going down than it was coming up.