According to Deleuze, in Nietzsche and Philosophy, Nietzsche holds an important distinction between active and reactive forces. One of the defining characteristics of reactive forces is they create a distinction between good and evil. In other words, they create a hierarchy. An example of reactive forces is what Nietzsche terms resentment, and is associated with 'slave morality'. The problem with resentiment, as a reactive force, is it says No to life, it is a negation instead of affirmation. We can think of the command 'Thou Shalt Not' as a illustration of reactive forces. The problem of resentment, according to Nietzsche, is we are unable to admire (or even love!) our enemies:
'How much respect has a noble person for his enemies! and such respect is already a bridge of love. After all, he demand his enemy for himself, as his distinction; he can stand no enemy but one in whom to be honored. Conversely, imagine "the enemy" as conceived by a man of resentment - and here is precisely is his deed, his creation: he has conceived "the evil enemy", "the evil one" - and indeed as the fundamental concept from which he then derives, as an after image and counterinstance, a "good one" - himself.' (The Portable Nietzsche, p452)
In other words, resentment, as a reactive force, generates an evil (the other), which produces a good (us). It is hard not to realise that resentment is (omi)present in today's world. Is the war on terror not a war fueled on resentment? We have the axis of evil as the other, and the "good one" as the 'civilised' west (or even the 'coalition of the willing'!)
The problem with resentment is it not only causes a group to resent others as evil, it also acts to repress those who resent. As Deleuze and Guattari would say it is 'desiring our own repression.' An example from a film can illustrate the process of desiring our repression through resentment.
In V for Vendetta a fascist government gets (democratically) voted into the UK government. On the whole, the fascist government gains power through an emergence of resentment of the other, which is viewed as evil. Once the fascist party is in power the removal of the other from the UK occurs. Anyone who is not white and heterosexual is removed from the UK. Through removing the other the British people repress themselves. Instead of affirming life they negate life through creating a majoritarian identity. The majoritarian identity functions as an inhibitor on what people can become. This is the important (ethical) point to realise. That resentment, as a reactive force, represses those who resent.