Happiness is.....

....watching old Fox Spider-Man cartoons on YouTube and eating some sloppily made egg and bulk meat (corn beef I think?) sandwiches.
The happiness is only temporary though. After the cartoon ends, I have nothing left to watch. After I have finished eating the sandwiches, they are gone. All happiness is only temporary.

On the other hand, joy is everlasting. Unlike happiness, it's more than just a feeling. You can have it when you mourn or are excited. It can feel like it comes deep within you, and you may not be able to explain it when your current situation dictates that you should be angry or depressed. Joy is the result of when you no longer feel guilty from your wrong doings. You acknowledge the forgiveness of God and experience His love. And it strengthens you. Joy does not make sense, but you know it's good.
You [God] will show me the path of life;
In Your presence is fullness of joy;
At Your right hand are pleasures forevermore.
Psalm 16:11 (NKJV)
In Heaven, I'm going to eat a humongous sandwich.
Actually, I think in Heaven there will be better things.
Bam.