From my variety of readings, I simplify that humans are in a state of joy when they thrive. And they thrive when they are able to showcase what (anything) they create and believe it seen, heard, or appreciated by others - I guess it peps up their ego, being social animals and builds some joy out of that supposed recognition.
As I was reading Harry Frankfurt’s “On Truth” I came across another definition for Joy. And this seems to be internally driven rather than externally and socially driven. He derives this from seventeenth-century Portuguese-Dutch-Jewish philosopher: Baruch Spinoza and it is a condensed version extracted as below:
Spinoza explained the nature of love as follows: “Love is nothing but Joy with the accompanying idea of an external cause” (Ethics, part III, proposition 13, scholium). As for the meaning of “joy,” he stipulated that it is “what follows that passion by which the…[individual] passes to a greater perfection” (Ethics, part III, proposition 11, scholium).
Now, if a person who experiences joy recognizes that the joy has a certain external cause—that is, if the person identifies someone or something as the object to which he owes his joy and on which his joy depends—Spinoza believes that the person inevitably loves that object. This is what he understands love to be: the way we respond to what we recognize as causing us joy. On his account, then, people cannot help loving whatever they recognize as being, for them, a source of joy.
Frankfurt, Harry. On Truth (pp. 39-44). Knopf Doubleday Publishing Group. Kindle Edition.
I try to reduce this into something that I can summarize to myself, handle and use “Joy derived from the objects that one cant avoid loving” or just even more simply “Joy from that you love from your heart”