Why is a lack of joy in serving God considered such a serious problem?

This source-based Hagut Yosef essay explores the question: Why is a lack of joy in serving God considered such a serious problem? The canonical Hebrew article develops the theme through Torah sources and reflection on human life. This localized discovery layer preserves the source’s meaning and identity and does not add new halakhic, historical, psychological, medical, legal, political, scientific, or empirical claims beyond the Hebrew source.