Chasidut על ברכות 60:29

A great and powerful king once invited one of his loyal servants to accompany him to his treasure ‎chamber where he displayed a store of jewels and other valuable artifacts. The servant was ‎overjoyed at the king having taken him into his confidence by showing him all his valuable ‎treasures. He became proud to be a servant to such a powerful king. Upon reflecting on this ‎however, he suddenly was overcome with trembling when thinking about what a great wrong it ‎would be to disregard even a minor paragraph in the law books the king had issued to his subjects ‎to live by. The psalmist’s words reflect a similar dilemma. How can one at one and the same time ‎be in awe and full of joy? The Talmud B’rachot 30, tries to answer this apparent ‎contradiction by understanding the latter half of the verse as: “when in a place where merriment is ‎the rule, do not forget that it behooves you to be trembling, seeing that you are always in the ‎presence of the Lord.” Abbaye, who, when in an extraordinarily happy frame of mind, was ‎reminded of this by a colleague, responded that as long he was wearing the phylacteries on his ‎head, this served him as a reminder not to forget this injunction.‎