"If a person comes and preaches some other Jesus than the one we preached, or if you receive a different spirit than the one you had received or a different gospel than the one you embraced..." (cf. 2 Cor. 11:4).
"Those who worship false gods turn their backs on all God's mercies," (cf. Jonah 2:8, NLT)
On Mount Areopagus or Mars Hill in Acts 17, Paul mentioned to the Athenians that he had noticed a shrine "to the unknown God." They were unwittingly worshiping God without knowing who He is! But we can worship unknown gods ourselves by the false worship of God, putting Him in a box, or diminishing His deity or glory. It may have all started when Satan told Eve that she could be "as the gods." Men have historically tried to "make a name for themselves" (cf. Gen. 11:4) since the tower of Babel. It is obvious to the pious man that people today aren't interested in being godly anymore, but in being gods, as Satan deceived Eve "You shall be as gods."
In humanism, they deify man and dethrone God: "Glory to man in the highest" so to speak. Actually, the Greeks of antiquity thought of humanism in the terms of man being the "measure of all things" ("homo mensura" from Protagoras). In other words, starting the calculus with man, not God in the equation.
What I want to point out is that we all can be idolaters without our knowledge, but thank God it's only he who knows the right thing to do and fails to do it is sinning: we sin in ignorance and fall short of true worship in spirit and truth--God for who He really is in reality. When God loses His awe or becomes commonplace and trite, and the pizzazz of worship seems perfunctory and we even become frauds at worship because of lack of sincerity but in hypocrisy, we are committing idolatry. We must give God his due worship for that is what worship is: what one is worthy of.
We can have many false gods that we invent and concoct or imagine. God demands Number One Priority and first place in our hearts. Anything that takes God's place in our life and removes Him from the equation or picture and inserts ourselves is idolatry. We are to fear God, so fearing anyone else is idolatry God created man in His image but Voltaire said that man has created God in his image: we imagine that God is like us only more so!
But we are only in His image so we can worship, love, know and serve Him, not so we can look to Him as our equal or that He is like us. It was the Greek pantheon that was created in man's image: the gods lusted, got drunk, and deceived just like men, and it was that philosophers like Socrates, Plato, and Aristotle were offended by this image of God as they saw Him: Especially in being the Supreme Good, the standard of perfection and goodness.
We are not to quarrel with our Maker (cf. Isaiah 45:9) and worship the true and living God as we are commanded and see ourselves in the true light of Scripture as sinners in need of salvation. We have no glory of our own and our glory is the gift of God. We are not to trust anyone but God and that means any false senses of security and false hopes. But God is no respecter of persons and demands we worship Him no matter who we are; there's no partiality with God and He shows no favoritism. We are all born sinners in need of grace! God levels the playing field and puts us all in the same boat. Even as believers, there is no caste system or elitism and we are all one in Christ (cf. Gal. 3:28; Col. 3:11).
Now, there are so many ways to commit idolatry that no one can be immune from sin. It's the First Commandment and also the greatest and what the others depend on. You could say that all other sins are corollaries of this one; failure to let God be God. We aren't just appeasing an angry God but rendering Him all that is due to His glory. We find out that the fear of the LORD is the beginning of wisdom and this it's the first base with God. The definition of a Victorian Englishman is a self-made man who worships his creator. The roots of self-adulation, self-admiration, and narcissism are obvious.
Now, just think of the typical American. In primitive times men worshiped creation such as the sun or moon and had gods for everything like Baal the fertility god. Israel had to be deported to Babylon and taken captive before learning its lesson not to commit idolatry with the false gods of Canaan. But we are no better today, though not pagan worshiping idols of stone or clay. Just wonder what impresses you or what your security is in. There's hero-worship of celebrities, politicians, experts, academics, and athletes.
What's more, there's the worship of intelligence, beauty, college degrees, technology, success, security, against loss of it in ID theft, job security, the hype of media or a moment in the limelight, one's party, church, or nation, military superiority, sexuality, toys big and small, but most of them can be included in the lust for fame, power, and fortune instead of seeking God's will. John sums up all sin as either lust of the flesh, the lust of the eyes, and the pride of life (cf. 1 John 2:16).
People are on a mad search for happiness no matter the cost and no matter whom they worship along the way in a dog-eat-dog world of survival of the fittest and might become right. What America has become is a materialistic society that survives on greed and possessions. It's become a competition of keeping up with the Jones and a society that sees itself as haves and have-nots. People aren't satisfied with what God blesses them with and seek riches no matter the cost to their honor or integrity.
A word to the wise is sufficient: "Thou thoughtest I was altogether as thyself" (cf. Psalm 50:21).
CAVEAT: To worship God for who He isn't in reality as some figment of your imagination or anything less than who He is (human thoughts of God) make you an idolater like Luther said to Erasmus of Rotterdam: "Your thoughts of God are too human." Like so many sects that are heretical and teach another Jesus (not divine), and selling him short: we must label this as idolatry. Soli Deo Gloria!