For one thing, every individual has an opinion as to which sins are the most grievous. To the inmate in a prison, the most vile offenders are those who abused children. To the parent whose child was killed by a drunk driver, drunk drivers would be at the top of his list. To the patriot, espionage or treason would likely top his list. To the wife deserted for another woman, adultery would certainly be in the top one or two. In other words, our lists would vary based upon our life experiences; they would be subjective.
My list, given in the "David Letterman format," would be: 10) Hypocrisy; 9) Stealing; 8) Greed; 7) Homosexuality; 6) Deceit; 5) Adultery; 4) Child molestation; 3) Murder; 2) Abortion; and 1) Idolatry! Of course, that list changes from time to time, depending upon my mood and current "pet peeve." When I am feeling patriotic, especially during political campaign seasons, I view misleading ads as a form of treason; political deception is nothing but the corrupting of our democracy! When I am going through a financial struggle, covetousness loses its distastefulness.
For the "really spiritual individual," the list would be exactly like God's list; like the Ten Commandments. And, that would be very unfortunate indeed. For you see, that individual's list would sentence him or her to hell! The Bible says that no human being is able to obey all of God's Law all of the time: all have sinned (Acts 13:39; Rom. 3:23; Gal. 2:16). Paul wrote that the purpose of the Law was not to save man, but was given to reveal to man that he needed a Savior (Gal. 3:19-25). So you see, even God's "top ten" list is not intended to be a prioritized list of the greatest to the least sins. To God, sin is sin! A sinner needs a Savior!
But if you were to ask God, "For what sin do You actually sentence a man to hell?"; He would say, "For the rejection of the Holy Spirit's evidence to your heart and mind concerning the fact that I sent Jesus Christ, My only begotten Son, to pay for your sins." In Matthew 12:22-32, Jesus, empowered by the Holy Spirit (v. 28; see also Lk. 4:18; Jn. 3:34; Acts 10:38), worked a miracle, a sign, that the Jews might believe (1 Cor. 1:22). When they attributed His miracle to Satan, they blasphemed the Holy Spirit. In other words, they did not believe the evidence the Spirit had provided, that they might be saved. Consequently, there is no way they could be saved. They committed the unpardonable sin!
Regardless of what sin you hate most in others, Jesus died for YOUR sin!