Christianity's famous list of Seven Deadly Sins fails to provide very useful guidelines of behavior in both theory and in practice.
In practice, most churches today ignore the seven deadly sins, eliminating even the potential for applying them to the rich and powerful. When was the last time you read or heard of any conservative evangelical churches - usually very vocal about how Christianity is needed for morality - say anything against gluttony, greed, envy, or anger? The only "deadly sin" which most have retained is lust, which might explain why it's been expanded in so many directions.
The theory isn't much better, though, because these sins focus on people's inner, spiritual state to the exclusion of their outward behavior -- not to mention their impact on others. Thus anger is bad, but not necessarily cruel and barbaric behavior which cause suffering and death. If you can argue that you have tortured and killed others out of "love" rather than anger, then that's not so bad. Similarly, if you can argue that you possess extensive material goods and temporal power not because of pride or greed, but because God wants you to, then that's not a sin and you don't need to change.
In theory, some could promote a more egalitarian society. Gluttony, for example, argues against any one person consuming so much that others are deprived. In practice, religious authorities rarely apply these standards against the behaviors of the rich and powerful; instead, they have been more useful in keeping the poor in their place and thus maintaining the status quo. Religion is frequently used to promote ideologies which help people accept their lot in life rather than struggle for something different and better.
Furthermore, there are no intellectual sins of any sort here. Adopting or promoting beliefs on the basis of irrational feelings and without empirical evidence isn't a problem. Not even lying is a deadly sin here -- lying out of love or in the service of God, for example, is less sinful than being angry over injustice and the lies of others. What kind of system is this? This is why secular, atheistic philosophies have not retained or perpetuated these "sins" in any way.
Origins of the Seven Deadly SinsIn Christian tradition, sins with the most serious impact on spiritual development were classified as "deadly sins." Christian theologians developed different lists of the most serious sins. John Cassian offered one of the first lists with eight: gluttony, fornication, avarice, anger, dejection (tristitia), sloth (accedia), vainglory and pride. Gregory the Great created the definitive list of seven: pride, envy, anger, dejection, avarice, gluttony and lust. Each of deadly (capital) sin comes with related, minor sins and are contrasted with seven cardinal and contrary virtues.
Seven Deadly Sins in DetailDeadly Sin of Pride: Pride (Vanity), is excessive belief in one's abilities, such that you don't give credit to God. Aquinas argued that all other sins stem from Pride, so critiques of the Christian notion of sin generally should start here: "inordinate self-love is the cause of every sin...the root of pride is found to consist in man not being, in some way, subject to God and His rule." Among the problems with Christian teaching against pride is that it encourages people to be submissive to religious authorities in order to submit to God, thus enhancing institutional church power. We can contrast this with Aristotle's description of pride, or respect for oneself, as the greatest of all virtues. Rational pride makes a person harder to rule and dominate.
Deadly Sin of Envy:
Envy is a desire to possess what others have, whether material objects (like cars) or character traits, like a positive outlook or patience. Making envy a sin encourages Christians to be satisfied with what they have rather than object to others' unjust power or seek to gain what others have.
Deadly Sin of Gluttony:
Gluttony is usually associated with eating too much, but it has a broader connotation of trying to consume more of anything than you actually need, food included. Teaching that gluttony is a sin is a good way to encourage those with very little to not want more and to be content with how little they are able to consume, since more would be sinful.
Deadly Sin of Lust:
Lust is the desire to experience physical, sensual pleasures (not just those which are sexual), causing us to ignore more important spiritual needs or commandments. The popularity of this sin is revealed by how more gets written in condemnation of it than for just about any other sin. Condemning lust and physical pleasure is part of Christianity's general effort to promote the afterlife over this life and what it has to offer.
Deadly Sin of Anger:
Anger (Wrath) is the sin of rejecting the Love and Patience we should feel for others and opting instead for violent or hateful interaction. Many Christian acts over the centuries (like the Inquisition and Crusades) may seem to have motivated by anger, not love, but were excused by saying the motivation was love of God, or love of a person's soul — so much love that it was necessary to harm others physically. Condemnation of anger as a sin is useful to suppress efforts to correct injustice, especially the injustices of religious authorities.
Deadly Sin of Greed:
Greed (Avarice) is a desire for material gain. Similar to Gluttony and Envy, gain rather than consumption or possession is key here. Religious authorities too rarely condemn how the rich possess much while the poor possess little — great wealth has often been justified by claiming that it's what God wants for a person. Condemning greed keeps the poor in their place, though, and prevents them from wanting to have more.
Deadly Sin of Sloth: Sloth is the most misunderstood of the Seven Deadly Sins. Often regarded as laziness, it is more accurately translated as apathy: when a person is apathetic, they no longer care about their duty to God and ignore their spiritual well-being. Condemning sloth is a way to keep people active in the church in case they start to realize how useless religion and theism really are.