Life is short in a sense that I know I won’t have time to learn about everything there is to learn. I won’t have time to study and understand the proof of Fermat Last Theorem, the latest breakthroughs of physics. I won’t be able learn piano like a professional or violin. I know that I won’t have time to read many classic of literature, etc. I can choose to do certain things but now I have to choose where to focus my time.