There is a phase of parenting where it's beneficial for mom and dad to both have a blind eye and a deaf ear. (I'm indebted to Spurgeon for this insight).
This is not the case when children are very young, like my near-two year old son. Then parents, if they are to avoid busted lips and wearing out their welcome at the ER, need not only keen eyes and sharp ears but the power to see into the future (ex: "unless I barricade the bathtub, he will climb in it fully dressed, soak himself, and then run like a crazed dog throughout the house").
But my subject is older children and my meaning is expressed in plain language by Solomon, in the book of Ecclesiastes (7:21): "Also take no heed unto all words that are spoken; lest thou hear thy servant curse thee." The margin says, "Give not thy heart to all words that are spoken"--do not take them to heart or let them weigh with you, do not notice them, or act as if you heard them."
Thinking of the conflicts that arise in my household with older children, I find Spurgeon's words (which I will adapt to my subject) very useful.
You will find that even those who live with you are not always singing your praises, and that when you have displeased your most faithful children, they have, in the heat of the moment, spoken fierce words which it would be better for you not to have heard. Who has not, under temporary irritation, said that of another which he has afterwards regretted? It is the part of the generous to treat passionate words as if they had never been uttered. When a man is in an angry mood it is wise to walk away from him, and leave off strife before it be meddled with; and if we are compelled to hear hasty language, we must endeavor to obliterate it from the memory, and say with David, "But I, as a deaf man, heard not. I was as a man that heareth not, and in whose mouth are no reproofs." Tacitus describes a wise man as saying to one that railed at him, "You are lord of your tongue, but I am also master of my ears"--you may say what you please, but I will only hear what I choose.
Likewise, turn a blind eye to sights that can be overlooked without detriment to the whole family. After 1,000 reminders to keep a clean room, a 1001th will only exasperate your relationship. It is time to gaze with the blind eye and use the good eye to look for better opportunities in the future.
Blessed are the peacemakers, and one sure way of peacemaking is to let the fire of contention alone. Neither fan it, nor stir it, nor add fuel to it, but let it go out of itself. Parent older chlidren with one blind eye and one deaf ear.