The Gemara quotes a verse in Iyov 24:14 as follows:

לָא֡וֹר יָ֘ק֤וּם רוֹצֵ֗חַ יִֽקְטָל־עָנִ֥י וְאֶבְי֑וֹן וּ֝בַלַּ֗יְלָה יְהִ֣י כַגַּנָּֽב׃

The murderer arises in the evening  To kill the poor and needy,  And at night he acts the thief.

This verse raises an important flag about zealotry. Whenever we find ourselves to excited about something we believe to be a good deed, we should double check if somehow it isn’t. It’s not that we cannot be happy and energetic to do good deeds but we should be a bit suspicious. It is strange how certain dubious mitzvos attract a lot of energy and excitement. Some examples:

• Most people when passionate about a topic, even if it involves l’shon hora, are quick to rationalize that “it’s for a good purpose”, yet when it comes to Shidduchim people often get an excess degree of yiras shamayim and are afraid to give over honest non-flattering information.
• People will go to extremes to fulfill various minhagim, even if they lead to machlokes and onaas devarim, though the minhag is not anywhere near as severe as לא תהיה כקרח ועדתו, or לא תונו איש את אחיו the prohibitions against verbal abuse and causing strife. Most ironic is that many customs in Shul are designed to reduce controversy, but often they become points of controversy. Such as one should pray out loud according to the congregation’s custom to avoid quarrels , but when another person hears the person praying “incorrectly”, they might shame him. Probably the Number one reason for quarrels is in Shul is someone yelling, “you’re not following my custom”
• We all know the Proverbial challah story, where the husband chastises his wife in front of the guests for forgetting to cover the Challah. One reason for the requirement to cover the challah so as not to “embarrass” the challah when we choose the wine for kiddush over the challah (Mishna Berura 274:41.)

for Video Shiur click here to listen:  Psychology of the DAF Pesachim 2