Halakhah su Salmi 145:19

One should stand to pray with reverence and humility and not in the midst of laughter, frivolity or purposeless matters, and not in the midst of anger. Rather [he should pray] in the midst of joy, like the words of comfort from the Torah, for example those that follow the redemption from Egypt [i.e. the blessing after the Recitation of the Sh'ma] or that follow Tehila l'David [i.e. Psalm 145], where it is written in it "He will do the will of those who revere Him" [and] "Hashem guards all those who love Him." [Psalms 145:19-20].