תַּ֗חַת אֲשֶׁ֤ר לֹא־עָבַ֙דְתָּ֙ אֶת־יְהוָ֣ה אֱלֹהֶ֔יךָ בְּשִׂמְחָ֖ה וּבְט֣וּב לֵבָ֑ב מֵרֹ֖ב כֹּֽל׃
because thou didst not serve the LORD thy God with joyfulness, and with gladness of heart, by reason of the abundance of all things;
Read kabbalistic (mystical) interpretation of Deuteronomy 28:47: and classical mystical sources.