The poet John Keats was obsessed with death and the fact that humans had a limited time on this Earth. This definitely translated into a unique view on the human condition.
Keats' father died when he was just 8 years old. His mother re-married and ended up losing the family's money to her new husband. Unable to look after her children when her second marriage soured, Keats was abandoned to the care of his grandmother.
His mother returned eventually, only to die of tuberculosis (the disease that would eventually kill John Keats himself).
The death of his father and misfortune of his mother affected the poet greatly. His poetry reflects a concern with fleeting time, impending death, and the importance of breaking away from routine and grasping life and enjoying nature and beauty before it's too late.
Ironically, John Keats died in Rome at the young age of 25. So his concern about death proved to be well-founded!