"Blessed is the man that walketh not in the counsel of the ungodly, nor standeth in the way of sinners, nor sitteth in the seat of the scornful. But his delight is in the law of the LORD; and in his law doth he meditate day and night. And he shall be like a tree planted by the rivers of water, that bringeth forth his fruit in his season; his leaf also shall not wither; and whatsoever he doeth shall prosper." -Psalm 1:1-3
I think it would be safe to assume that most Christians would want to be like that fruitful, prosperous tree described in verse 3. They want God's hand of power and blessing on their life. There's certainly nothing wrong with desiring those things.
The problem comes when we only apply part of the formula described here to get those results. There are a lot of Christians who pride themselves in applying the principle found in verse 1. (I know I've been guilty of this at times!) They are separated from the world and it's philosophies. They truly shun influence from people who want nothing to do with God. These are good things, but they're only part of the formula!
This is where the Replacement Principle comes in. God doesn't just want certain things to be removed from your life. There are also things He wants put in. The Christian life is not just about abstaining or separating from certain influences. It's about filling that void with something that glorifies God.
The first part of the formula is found in verse 1. The second part is found in verse 2. It's not all about despising the world, it's also about delighting in His Word. It's not just about removing something from your life, it's also about adding something to it. If you're seeking the blessing of God on your life, make sure you're applying the whole formula to it. If you don't you'll just end up being a frustrated, unusable vessel.
Here's a convicting question that will tell you where you're really at with this: Do you delight in the Word as much as you despise the world?
The truth is, our delight in God's Word should be greater than our disdain for the world.