Ignore your enemy or kill him- Roger Rosenblatt. From Rules for Aging: A Wry and Witty Guide to Life. Harcourt 2000.

Rosenblatt is also the author of Unless It Moves The Human Heart: The Craft and Art of Writing. Ecco 2011.

In this world you have to be oh-so-smart or oh-so-pleasant. For years I was smart. I recommend pleasant. -Harvey the Rabbit

So do I, generally. There is a special context, though, in which one can be smart by being pleasant. It occurs in one of those very unpleasant situations in life when you recognize that you are faced with an enemy of a particular sort - someone to whom you have done no harm, yet who, nonetheless, seethes with a hissing fury at the mere mention of your name, yips like a terrier whenever you enjoy good fortune, and bites the newspaper when there is a report of your success. Now, here is one person who is thinking about you. In an odd way, he lives for you. Your every move gives definition to his existence.
Ayn Rand created such a character in her nutty novel, The Fountainhead, with the critic who relentlessly savages the work of Howard Roark the architect, no matter how demonstrably wonderful Roark's work is. Rand painted the critic as one who would have no reason for being if he could not attack Roark at every turn. In Roark's presence, he glowers at the architect like a hungry rat - eyes squinting and burning - knowing that he is too small to devour his quarry, yet desperate to do damage, or, in the very least,to be noticed by Roark for the damage he attempts to inflict.
For his part, Roark ignores the man entirely. He goes about his work unconscious of this critic or of anybody who might interfere with his vision. HIs attitude has a kind of Nietzschean charm, but it protects him from bothersome disturbances. Finally, the critic cannot take being ignored any longer, so he confronts Roark with all the awful things he has written about the architect. He asks, half plaintively: "What do you think of me?" Roark, as if seeing the man for the first time, responds: "I don't think of you." The critic withers and slinks off.
It is Rand's version of the scene in Casablanca where Peter Lorre says to Bogart: "You despise me, don't you?" and Bogart replies: "I would if I bothered to think about you."
In the realm of normal human behavior (whatever that may be), it is probably impossible to be as oblivious as Roark is when there is someone around continually seeking to do you harm, indeed, whose bitter happiness seems to depend on it. Only a person with the hide of an elephant could really pay no attention when such an enemy is relentlessly firing insults and slinging mud. Who would not feel some slight hurt, if only because someone exists who is consumed with the desire to bring you low?
And yet, here - as in so many rules of aging - the trick is to do absolutely nothing. Nothing is everything. Ignore your enemy or kill him. If you pay no attention to him, he may not slink away, but he will grow increasingly desperate, increasingly incoherent, and (best of all) increasingly unhappy. The happier your life, the more miserable his. The truth is, that people of this peculiar stripe are their own worst enemy (admittedly, they have heated competition), and it constitutes one of life's delights to watch them go at themselves with all the bitterness and disappointment of which they are composed. To enjoy this, however, one must never give them a scintilla of assistance.
Of course, as the rule suggests, one can take a different approach, and, instead of ignoring one's enemy, one can murder him. If he is really getting to you, I advise that you do it. But you must kill quickly, suddenly, and anonymously, or it's no good- with a bomb, perhaps, or a flamethrower shot from a great distance. You want him dead, but you do not want him to see that it was you doing him in. If he knows it is you, all is lost. In that billionth of a second, he will die content that he got your goat and that all his efforts have finally paid off - which is the last thing you want.
For myself, I favor giving one's enemy life without parole instead of an execution. Think of it, the beauty of it: You are his obsession, and he is merely a bark in the night. The idea is not to care, not to pretend that you don't care, but to really not care. Trust me. You have just extended your enviable life.