This verse identifies our main problem. We want to conform to this world too much. We don't want to be considered an odd ball. We want to be able to have our fun, too. Pleasures of this world are only fleeting.
Spiritual joy is for all eternity.
We must allow God to renew us in our mind. We can't think the same old way we always have. It is only then that we will begin to understand the will of God. It is only then that we will understand what is good and acceptable and perfect. We must allow God to have our thoughts.