"The tragic sense of life"

Wiki seemed to be the only resource I could find on any information About this quote. It was a book written by Miguel De Unamuno y Jugo in the twentieth century and it's relevance to our class and "The Brothers Karamazov" seems to be that both these novels were written By believers of existentialism. Wiki claims:

Existentialism is a term applied to the work of a number of 19th- and 20th-century philosophers who, despite profound doctrinal differences,[1][2] generally held that the focus of philosophical thought should be to deal with the conditions of existence of the individual person and his or her emotions, actions, responsibilities, and thoughts.[3][4] The early 19th century philosopher Søren Kierkegaard, posthumously regarded as the father of existentialism,[5][6] maintained that the individual is solely responsible for giving their own life meaning and living that life passionately and sincerely,[7][8] in spite of many existential obstacles and distractions including despair, angst, absurdity, alienation, and boredom.[9]

My own feeling on the words is that they are telling you to live your life but understand the tragic and deathly sides to your own existence. By finding humor in death people can live their lives free of fear and anxiety understanding everyday on this side of the dirt (the top side) is a day that should be utilized. But I more than likely am mistaken in claiming this.