Put a song on your heart too whenever you need a quick lift. King Saul, Deborah the Prophetess and Elisha the Prophet all did when they were down (see Samuel I 16:16, Kings II 3:15 among other sources). It works. Even if you don’t play a musical instrument, hum your favorite melody or listen to your favorite music. Pick a melody that your mind associates with happiness.
Once we put a song on our hearts, we remember Hashem. And once we remember Hashem, we remember that everything is for the very best. Now we can really smile.