Proverbs 20:14 Halakhah

רַ֣ע רַ֭ע יֹאמַ֣ר הַקּוֹנֶ֑ה וְאֹזֵ֥ל ל֝֗וֹ אָ֣ז יִתְהַלָּֽל׃

’It is bad, it is bad’, saith the buyer; but when he is gone his way, then he boasteth.

Read halakhic rulings (Jewish law) on Proverbs 20:14: and classical halakhic sources.