Today’s practice: When you find an online comment or contribution that truly annoys you, put it on your desktop or bulletin board. It’s your own personal classroom for learning about difference, and practicing tolerance.

When companies, organizations or individuals set up their first social web presences, one of the things they often worry about is how to handle online criticism. In most cases, the now-recognized best practice is to err on the side of tolerance, accepting that some level of online criticism is part of life, and that the most effective and credible responses often come not from the community manager, but from the community itself.

That takes care of things as far as community managers are concerned, but what about social media users? I often hear from regular people (i.e., folks who are not communications or web professionals) who struggle with online criticism, too. The hostility of many online conversations feel inhibiting, a point that Frances Bula emphasized during our recent social media panel at the UBC Graduate School of Journalism. News and political sites, in particular, have become infamous for the inflammatory tone of their comment threads. And who feels energized by reading or participating in a social web site that is full of ad hominem attacks, profanity or garden-variety stupidity?

But I was reminded this week that one man’s garbage is another man’s treasure, when one of my favorite user-generated conversations was wiped clean. In this case, the conversation wasn’t online: it was on the walls of the ladies’ room just down the hall from my office.

As I have previously blogged, the quality of this bathroom graffiti has been one of the great delights of working at an art university. Many of its most inspired images and phrases have made it into my Twitter feed over the past few years, as you can see on the delightful gallery that got automagically curated by Twylah.

Bathroom wall with dryer turned into person

Before

Freshly painted bathroom

After

Many, but not all. When a visiting conference and an accompanying fresh coat of paint took hold in our building this week, we lost treasures like “Whatever turns me on, I put up my nose” (accompanied by a pretty remarkable drawing of a person with a penis up her nose) and “You are beautiful and perfect just the way you are” (which I’d been planning to transplant to my gym, where the message is much-needed).

The penis-filled nose, in particular, was cited by one of my colleagues as a drawing we were better off without. And I get it: that image was a lot to take, especially if you’re just trying to nip out for quick mid-meeting pee.

But it’s the moments when we are confronted by something outside our comfort zone — by something ugly, transgressive or simply rude — that often produce the greatest growth. The obscene image, the idiotic blog comment, the hostile post on a Facebook wall: they get under our skin. They irritate us until we find a way to understand why somebody would write that, until we grapple with the painful reality that people are profoundly different from one another, until we grow a thicker skin.

So the next time you find yourself wishing that a website moderator would exert firmer control over a web space or presence, look more closely at the comment or contribution that is irritating you the most. Bookmark it, reread it, turn it into your desktop picture, mull over and ruminate on it. Make the most annoying parts of the social web into the parts that you know most intimately, and silently thank the Internet’s most egregious trolls for delivering a lesson in comprehending human difference.