I’m not depressed (at the moment, well maybe a little), just feeling philosophical.
Edit: the idea of this came to me because I was pondering why people fight so hard to beat diseases and live a few more years. What are they planning to do? Why exert effort just to be here longer when you don’t have a reason?
Just why?
It’s whatever you decide it to be. You are right - nothing matters in reality, but you can assign importance to things yourselves and as you said “amuse yourself to death”.