For men shall be lovers of their own selves, covetous, boasters, proud, blasphemers, disobedient to parents, unthankful, unholy, 2Ti 3:2 The `Me` generation.     Self Worship is idolatry.

Yes, all the Sins mentioned in the above verse identify Pagans but the word that I think is the most overlooked Sin is that of being Unthankful.   

Know the Lord: it is he that has made us, and not we ourselves; we are his people, and the sheep of his pasture. Psm 100:3 The most egregious sin is the sin of unbelief in the Lord which results in the idolatry of Self Worship.

When a person Understands the truth of Psm 100:3 their mouth will be full of Praise and Thanksgiving for the gift of Life, their talents, their family, their friends and all the blessings of His Creation.   

While on the other hand...   

The fool has said in his heart, There is no god.     They are corrupt, they have done abominable works, there is none that does good. Psm 14:1 To not acknowledge the Lord Jesus Christ is to effectively confess unbelief in Him.      Society today considers the notion of the Lord Jesus Christ as obsolete and resents the injection of Him into any discussion.

To not be Thankful and Praiseful to God is a condition of Unbelief in the Heart so that they effectively are saying "There is no God.   I have made myself."