Question:

Unsaved people can experience the feeling of love, joy, peace, etc. God gave us emotions for a reason, and I understand that even we who are saved have un-sanctified emotions. Now when I worship, I experience the Lords presence (the Spirit), and I also experience joy.

How does the Spirit produce joy, for example, in us? Does he enter us and "amplify" our emotions? Does he, because he himself is joyful, allow us to see him and our souls thereby become "like him". How specifically does it work? Wouldn't there be spritual joy and human joy, and how would they compete?

Answer:

Emotions and feelings are things which are common to humanity as a whole, whether believer or unbeliever.  However, those emotions are not the same for both believer and unbeliever.  And the reason why is that the object of their affections are not the same.

The believer's entire being—both intellect and emotions—are focused on that which is uncreated: God and his glory.  The unbeliever, by contrast, has his affections set on the things which are below: earthly things and his own glory.

So, when Paul speaks of the fruit of the Spirit what, he has in view is the result of the work of the Holy Spirit.  It is the Spirit who unites us to Jesus Christ and his redemptive work, as Paul makes clear in Galatians 5:22–24, "But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, self-control; against such things there is no law. And those who belong to Christ Jesus have crucified the flesh with its passions and desires."

The Holy Spirit makes us "belong to Christ Jesus."  And as a result of that work in us, there is a difference in how we live.  Christ not only redeems us from the guilt of our sin, but from its power as well.  Therefore, as a result of our being in Christ by the Spirit we will love others in a way we didn't before, We will have a joy we didn't have before, and so on.

This joy is not the joy which unbelievers experience.  They experience joy, but it is as a result of earthly, temporary things.  Their joy is the fruit of the flesh, not the Spirit.

Just one last thought.  You want to be careful to distinguish between the Holy Spirit himself and your emotions.  The emotion you experience is not the Holy Spirit himself.  Your emotions are still a fallible, created, and fallen aspect of your being.  But they are now, by God's redeeming grace through Christ and given to you by the Spirit, directed toward God and thus are the fruit of God's grace.

I might recommend reading Jonathan Edwards' The Religious Affections and/or Charity and its Fruits.