[Ieghaehia9]

Discarding with explanation can sometimes be used to effect too.

For example, suppose a character sends a spy to accomplish an objective. Meanwhile, another group of people are also trying to do this, which will benefit the main character, although the main character is unaware of this. The second group gets there first, and even though there was considerable buildup to the spy's mission, in the end, his presence doesn't matter (much).

If you want as lean a story as possible, you would cut out the spy's mission altogether, but its presence gives a sense of realism, because the character in the story doesn't know ahead of time that sending the spy would be redundant.