C.S. Lewis and Pastor John Piper have both influenced me in this matter of joy. C.S. Lewis titled his autobiography, "Surprised by Joy." While I found it a difficult book to read, he writes about how he didn't want to become a Christian, but over time, his resistance melted like a snow man and the joy of Christ came in! Pastor Piper has written and spoken extensively on the subject, and has emphasized how God has commanded us to find joy in Himself.
In Deuteronomy 28:47-48, we see how seriously God takes this matter. "Because you did not serve the Lord your God with joyfulness and gladness of heart, because of the abundance of all things, therefore you shall serve your enemies whom the Lord will send against you, in hunger and thirst, in nakedness, and lacking everything. And he will put a yoke of iron on your neck until he has destroyed you."
Is God and egomaniac? No. I don't believe so. He IS the Creator of all things, and knows that there is no way we can fully know joy apart from Him. He wants us to seek joy for our benefit! We can never fully know joy in anything else. Psalms 16:11 says it beautifully, "You make known to me the path of life; in your presence there is fullness of joy; at your right hand are pleasures forevermore."
We can be sure of this for one who would follow Christ...He will
relentlessly pursue us to relinquish every last thing big or small which
would hinder or steal our joy in Him alone. He will work overtime to
help us see that there is no way we will know real joy apart from Him.
He made us to know fullness of joy in Him, nothing or no one else.