The secret is to escape the repugnance of the apparent attack upon one's sensitivities. More likely than not, the offending slur or handiwork of the other party is completely unintended. It is our own bloodymindedness which insinuates the mannerism and misinterprets it as a slight. Better to "let the shit wash down the street" than to step in it! But the primary benefit of constrained comportment is the ability it affords to by-pass or ignore the problem in the first place. There is a risk that such smugness may amount to plain arrogance; but how much better is that than the indignity of fatuous anger! Besides it is unnecessarily mercenary to presume that the conduct of others is always directed at oneself. I much prefer to cultivate even the alleged perception that there is something wrong with them!
Not surprisingly it is the understanding of the detail surrounding the etiquette of others which adds depth and substance to the knowledge. If nothing else the analysis defeats the conceit of a personal insult. What it is that prompts people to act as they do is an arduous study and certainly not one to be accomplished in a matter of minutes. It also doesn't help the conviction of inadequacy to imagine that its resources are shallow. Life is a complicated experience! Too often we are shockingly reminded that what we had first imagined about others is completely mistaken. Nor does the recognition lie merely in the passage of time. If one is not prepared to survive the endurance of sometimes lengthy exploit, then the only decision approaching any accuracy is to forego the condemnation of the performance in the first place.
If all this reeks of Pollyanna then consider if you will the bluntly pragmatic option. It is possible to avoid the answer if there is no question. Rather than the discombobulation of taxing condescension, elect instead to add the event to a repertoire. There is no reason that the daily emissions of others cannot be added to a novel-like inventory. We needn't rely upon the likes of Dostoyevsky for insight and savage humour. If we awaken our mind sufficiently the moral problems posed by humanity and its suffering are well within our reach. But we must at least try as best we can to adopt mature behaviour; otherwise we relinquish ourselves to immediate defeat.
The collateral to mature behaviour is that it paradoxically turns our sights inward. That alone contributes sufficiently to the abandonment of conflict with others. But more importantly it enables us to appreciate our own capital (rather than diminishing that of others). Mature behaviour is superlative not because it imitates some synthetic gesture but because it draws upon the elemental resources within us. It is altogether misguided to presume that unflattering conduct benefits anyone - any more than there is something inherently attractive about a howling child. If we fashion ourselves to have acquired any wisdom from the past then we must react accordingly, failing which we're either slow learners or imbeciles.
There is considerable humour that abounds within the compass of knowledge. By indulging our whim we enlarge more than life's jocularity but also its satire, irony and drollness. It provokes a dry amusement if nothing else. I have known a man who succeeded to dismiss what he considered to be the inconsequential behaviour of others by professing that "it is the privilege of the masses to mock their betters". Though I like the tone of the quip I rely more favourably upon the premise that active is better than passive. There is some threat of isolating oneself completely from others if there is no attempt made to comprehend them. In that respect mature behaviour is not entirely effortless. But I have yet to convince myself that impulsive is better than careful.