That brings sadness and tension into your life. You keep finding out that even your work cannot give you that wonderful, happy life. All your work cannot provide the real meaning of your life. This is what Ecclesiastes makes clear in Ecclesiastes 2:22–23. To live for your work only is also in vain.
23 Tous ses jours ne sont que douleur, et son partage n'est que chagrin; même la nuit son cœur ne repose pas. C'est encore là une vanité.