I cook lunch to justify my existence
What does cooking food have to do with justifying your existence?
Well, I know that we definitely need food in order to survive.
Knowing why you do things is a great start that many don't have. But look beyond just existing, find what makes you happy.
That's true. There are things that I enjoy too.
Exactly! Start spending your time doing some of these things that you enjoy. This I am sure will begin to make your life feel much more rewarding!