Act joyously. These two words are powerful. They work. Test it out congruently and see for yourself how effective this formula is.
If it's so easy, how come everyone isn't radiating joy? I didn't claim it was easy. It's simple to say, but the very fact that not everyone consistently applies it shows that it doesn't come naturally to many people. It takes effort. And it also takes belief in the process. You can counteract the effects of acting joyously by holding back or by repeating to yourself, "This won't really work."
"Act with enthusiastic joy and you will actually experience it," was expressed by Rabbi Moshe Chaim Luzzatto in his classic work "Path of The Just" written in 1740. Since then many professionals in the field of human emotions have repeated this formula. It worked then and it still works now. The more flexible someone is with their emotions, the easier it is for them to apply this. Experiments with biofeedback technology and the testing of hormones in the blood after acting joyously have proven its effectiveness.
(From Rabbi Pliskin's "Happiness", p.34)