Joy isn’t necessarily happiness. One can be joyful without being happy all the time.
Happiness is a temporary emotion. “That is because happiness is an emotion in which we experience feelings ranging from contentment and satisfaction to bliss and intense pleasure, whereas joy is a stronger, less common feeling than happiness. We experience joy when we achieve selflessness to the point of personal sacrifice.” (Island Packet)
While this perspective encourages us to self-sacrifice, I contend that joyfulness can be attained without necessarily requiring self-sacrifice. Joy is an understanding of one’s own wants and desires, and knowing how to achieve that which is most important in your life. Joyfully moving through this world is one of the most important things we could do, if we only allowed ourselves to do it.