You ask for some way of completely eradicating irritability. The inclination to irritability is given us to use against sin, and we were never meant to use it against our fellow men. When we do, we act contrary to our true nature.
When God, using our conscience, calls us to righteousness and yet our self-will opposes Him, He respects our freedom and lets our own will be done; but then, alas, our minds grow dull, our will slack, and we commit iniquities without number. On the other hand, the fruits of the spirit are soon granted to them who follow the commandments of Christ our Lord.
The weather shifts from cloudy to clear and then back to rain; thus it is with human nature. One must always expect clouds to hide the sun sometimes. Even the saints have had their dark hours, days and weeks. They say then that 'God has left them' in order that they may know truly how utterly wretched they are of themselves, without His support. These times of darkness, when all seems meaningless, ridiculous and vain, when one is beset by doubt and temptations, are inevitable. But even these times can be harvested for good. The dark days can best be conquered by following the example of St. Mary of Egypt. For forty-eight years she dwelt in the desert beyond Jordan, and when temptations befell her and memories of her former sinful life in Alexandria beckoned her to leave her voluntary sojourn in the desert, she lay on the ground, cried to God for help and did not get up until her heart was humbled. The first years were hard; she sometimes had to lie this way for many days; but after seventeen years came the time of rest. On such days stay quiet. Do not be persuaded to go out into social life or entertainment. Do not pity yourself, seek comfort in nothing but your cry to the Lord: 'Haste thee, O God, to deliver me! Makes haste to help me, O Lord (Psalm 70:1)! I am so fast in prison that I cannot get forth (Psalm 88:8),' and other such appeals. You cannot expect real help from any other source. For the sake of chance relief do not throw away all your winnings. Pull the covers over your head; now your patience and steadfastness are being tried. If you endure the trial, thank God who gave you the strength. If you do not, rise up promptly, pray for mercy and think: I got what I deserved! For the fall itself was your punishment. You had relied too much on yourself, and now you see what it led to. You have had an experience; do not forget to give thanks.
The lives of men are subject to drastic changes. These changes are gradual at times; at others, lightning quick. But even those of us who enjoy long years of opulence and fame can find no consolation, no gladness, unless our heart is illumined by the steady light of peace. It is this peace that we must seek, it is for this peace that we should pray. The peace that our Lord gave to His disciples and to all those who really have faith in him.
But if you are fearful of becoming self-righteous from working for your own salvation, or afraid of being overcome by spiritual pride, examine yourself and observe that the person who is afraid of becoming self-righteous suffers from blindness. For he does not see how self-righteous he is.
One must clean the royal house from every impurity and adorn it with every beauty, then the king may enter into it. In a similar way one must cleanse the earth of the heart and uproot the weeds of sin and the passionate deeds and soften it with sorrows and the narrow way of life, sow in it the seed of virtue, water it with lamentation and tears, and only then does the fruit of dispassion and eternal life grow. For the Holy Spirit does not dwell in a man until he has been cleansed from passions of the soul and body. Only one thing may remain within a man, either the Holy Spirit or the passions. Where the Holy Spirit is, there the passions do not come near, and where the passions are, there the Holy Spirit does not dwell, but rather the evil one.
In patience is the assembly of all the virtues by which our souls are saved, as St. Ephraim says: He who acquires patience touches on every virtue; for he rejoices in sorrows, is well tested in misfortunes, is glad in perils, is ready for obedience, is filled with love, gives praise when provoked, is humble when reproached, is unwavering in misfortunes.
No one can be saved without the renunciation of his will, even though he might struggle fervently, for our will and our manner are like a bronze wall between us and God.
A life lived in the world can be as good, in the eyes of God, as one spent in a monastery. It is indeed only the keeping of God's commandments, love of all, and a true sense of humility that matter, wherever we are.
You must set about rooting out the very desire to have things pleasant, to get on well, to be contented. You must learn to like sadness, poverty, pain, hardship. You must learn to follow privately the Lord's bidding: not to speak empty words, not to adorn yourself, always to obey authority, not to look at a woman with desire, not to be angry and much else. For all these biddings are given us not in order for us to act as if they did not exist, but for us to follow: otherwise the Lord of mercy would not have burdened us with them. If any man will come after me, let him deny himself, He said (Matthew 16:24), thereby leaving it to each person's own will ... and to each person's endeavor: let him deny himself.
Pray that you may be granted the grace to read the Fathers with the right understanding, the grace to live up to the standards they put before you, and the grace clearly to see your own frailty. You will not long be left wanting and waiting. God will give you help.