תַּ֗חַת אֲשֶׁ֤ר לֹא־עָבַ֙דְתָּ֙ אֶת־יְהוָ֣ה אֱלֹהֶ֔יךָ בְּשִׂמְחָ֖ה וּבְט֣וּב לֵבָ֑ב מֵרֹ֖ב כֹּֽל׃
Et parce que tu n’auras pas servi l’Éternel, ton Dieu, avec joie et contentement de cœur, au sein de l’abondance,
Tanya
What's more, if one will be wicked in his own eyes he will feel embittered and depressed, and he will be unable to serve G-d with joyful and a glad heart. And (even) if he will not be grieved by this at all, this could lead to frivolity, G-d forbid!