What is the main lesson of "The Interlopers"?

One lesson that the narrative of "The Interlopers" presents is that people should not become mired in issues that are not essential to the quality of their lives.
The plot of Saki's story revolves around an ancient grudge that two young men have allowed to become foremost in their lives as they have inflamed the hatred between their two families, who once disputed a small tract of land:

The feud might, perhaps, have died down or been compromised if the personal ill-will of the two men had not stood in the way; as boys they had thirsted for one another's blood, as men each prayed that misfortune might fall on the other.

Of course, the old maxim "Be careful what you wish for" is also applicable to the narrative of "The Interlopers," as well as the senselessness of their feud, since misfortune does, indeed, befall the two enemies. Unfortunately, it has taken a disaster to effect a change of heart in the two men, and as fate would have it, this realization comes all too late. For it is only after the two men are pinioned under the fallen branches of a huge beech tree, lying hurt and helpless, that Ulrich von Gradwitz arrives at the understanding of the real insignificance of his feud with Georg Znaeym in light of their life and death situation. Unfortunately, when the two old enemies finally put away their feud, it is too late because they are confronted with death in the shape of fierce wolves who hear their cries for help.