אִ֭וֶּלֶת שִׂמְחָ֣ה לַחֲסַר־לֵ֑ב וְאִ֥ישׁ תְּ֝בוּנָ֗ה יְיַשֶׁר־לָֽכֶת׃
Folly is joy to him that lacketh understanding; But a man of discernment walketh straightforwards.
Read midrashic interpretation of Proverbs 15:21: and classical rabbinic exegesis.