“Sing aloud unto God our strength: make a joyful noise unto the God of Jacob. Take a psalm, and bring hither the timbrel, the pleasant harp with the psaltery. Blow up the trumpet in the new moon, in the time appointed, on our solemn feast day.”
Psalm 81:1-3, The King James Version

But why not every day? Why not in all circumstances? Think of Paul. Maybe it is because my small group is studying Philippians right now, but that his ministry is in the forefront of my mind. All the stuff that he went through, and still he rejoiced in his suffering. Not to mention all the stuff that Job went through.