for me Joy has that meaning of the Simple pleasures of life...you know when you're doing something you really like or when you receive something nice and unexpected, or chatting with a good friend while having chocolate and tea on a rainy day, or shopping and getting extra-stuff (don't get me wrong...not in the meaning of being material but like getting something nice that sometimes just makes your day). Or finding a nice and quiet place where you spend the day with a good book not noticing that the time goes by and last but not least knowing that you always have your loved ones by your side. Just...enjoying every moment of life and knowing that you definitely have more good moments than bad ones.
and of course while doing all this you forget/ don't care so much of the bad things that happened, or could happen.
Joy is something that makes you feel good about yourself, either 'cause you had a good day or either 'cause you did something nice for someone.
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hope i helped...it's all i could come up with... good luck with your project...if i can help more just tell me.
oh and about grammar errors in the text above...please feel free to correct them. i'm really sleepy and having a lazy day today