Another example of the proverb: "Hatred corrodes the vessel in which it is stored"
David has wasted the last years of his life obsessed with destroying Office Depot to the point where he was suffered from insomnia, depression, alcoholism, and now terminal cancer. Perhaps some good can come of this. David's life can serve as an illustration that one should seek early treatment for mental illness. Perhaps if David had sought treatment, his physical health wouldn't have suffered, and he would have dealt with the Office Depot matter in a more constructive way.