Major and Minor Calamities Are the Retribution of Vengeful Spirits

By nature, humans wish, hope, and desire. 
However, few fulfill all of their wishes, hopes, and desires. 
And everyone who has lived in this world died harboring bitterness and grief, major and minor. 
Beneath all suffering and tragedy lies untold bitterness and grief accumulated over for a long time.
When one carries out malevolent deeds throughout their lifetime, they open a path of ill fortune for their descendants.
To exact revenge for their bitterness and grief, vengeful spirits torment the descendants of those who wronged them.