The Greek philosophers in general and Christian thinkers after them have seen the emotions (passions) as innate parts of human nature. Even the Stoics, who seem to condemn the passions, really only condemn disorderly, irrational passions, as Aquinas and others have noted.
John Chrysostom cautions against anger, but he implicitly means disorderly anger, as he sees both anger (the irascible appetite) and desire (the concupiscible appetite) as essential, and therefore God-created, parts of human nature.
Yet surely both are naturally implanted, and both are set in us for our profit, both anger, and desire: the one that we may chastise the evil, and correct those who walk disorderly; the other, that we may have children, and that our race may be recruited by such succession. (Homily XVII on Matthew V.28.28)
Of anger Chrysostom says:
And what is the proper time for anger? When we are not avenging ourselves, but checking others in their lawless freaks, or forcing them to attend in their negligence.
And what is the unsuitable time? When we do so as avenging ourselves….(Homily XVI. Matt.V.37)
(One author met someone who said the Israelis must forgive the Palestinians for their attacks on children and turn the other cheek; but this pacifist then went on an length and vituperatively about a colleague who had failed to give the pacifist proper mention in an academic article. I think we have all encountered the type. It is easy to tolerate evils done to others.)
As someone in the comments mentioned, this analysis of the role of the passions creates a problem for the doctrine of creation: if man was created in a world without evil (and God had pronounced it “very good) and was immortal, why are these two passions clearly designed for a world beset by evil and death?
Presumably, in an unfallen world the energies that we feel as anger and desire would take different forms – but the forms are unimaginable. And what will they be look in the new creation, when death and evil will be no more?
My tentative guess is that God, know that his rational creates would sin and fall, create the universe ruled by transiency (and therefore death) and created human nature such that it had these passions so that man could face with courage the evils of the world and reproduce in his warfare against death.
But that is just a guess.