Job 14 - Job speaks of the futility of life without a future (on earth) after death, whereas a "dead" tree will "come back to life" with the presence of water, vs. 9. Yes, our world shows replenishing of dying forests, but no such "renewal" is seen in a graveyard. (We Christians know, however, that our bodies will be raised from the dead!)
Job 15 - Eliphaz thought himself a wise man, so he rebuked Job for his sins. He even accused Job of being "full of hot air" vs. 2. He also spoke of wicked people having a horrible life, vs. 20. Yet, he didn't have an answer when wicked people seem to live in luxury.
Job 16 - Job refers to his "friends" as "miserable comforters" vs. 2. He spoke of the hand of God against him to which he had no defense. He wished for someone to plead on his behalf to God, vs. 21. Praise God that we who know the Lord have a Mediator in Jesus!