Irritation means one of two things -- you are unable to get though to the other person, or you are no longer willing to try.
Maybe you are tired of beating your head against the wall, or find your fount of emotional strength exhausted, or your words fail you. It is also possible that you already tried your eloquent best and the other person simply cannot or will not listen.
Recognize which it is, and then either renew your effort to communicate with better clarity or do what you can to get away from the source of irritation.
Don’t waste another minute.
Because perpetuating anyone's state of irritation -- including your own -- is as bad as letting a faucet perpetually run water.