I mistakenly added some backstabbing beeyatches from my job as friends on my Facebook page. One eased my burden by defriending me (very unceremoniously, I may add) and I have now defriended AND blocked all three, the last two by association to the first. Was this the right call? I behaved rashly, I know, but sometimes my instincts are right on the money.
~Jilted at Job
The defriending and blocking combo may have been a bit of an overkill there, Courtney Love. Unless they literally stabbed you in the back, then that would have been a justifiable response. I understand the impulse, though. It's rather exhilarating to be able to eradicate someone's e-xistence with a mere click. If only that were true for other blights on mankind, like concept mustaches, HIV, or Steven Seagal's energy drink.
As I talked about a few weeks ago, blocking someone renders them unable to search for you, so on the unlikely chance that you want to be ceremonious to said beeyatches, you can always say you simply deleted your profile. This won't work, however, if you have mutual friends, because you might still show up in the "recent posts" feed.
Basic decorum dictates that you still behave respectfully toward the offending parties in person. Other than that, though, I don't see any big to-dos about defriending co-workers that really rub you the wrong way. (Read some of the most common reasons why people get defriended here). However, there have been lawsuits concerning supervisors who defriend employees, which can be construed as an act of retaliation, especially if that employee filed a complaint about something. I doubt that's the case for you, but it is something to be aware of in these lawsuit-happy, Boy-Named-Sue times we live in.
I'm assuming also, because you didn't mention it, that you probably don't work directly with said beeyatches, and that defriending them hasn't negatively affected your work environment or ability to be productive. If it has, then you might have to eventually take it up with your boss. Backstabbing beeyatchery can and does translate to the real world at times. This is one reason for better vetting our Facebook friends that we have to interact with on a regular basis.
I think a general rule of thumb for defriending is if you saw a particular Facebook friend on the street and had the urge to hide behind the nearest hipster to avoid contact, you should probably just cut that person loose. Social media can create a false sense of intimacy, and because of that, it can sting when someone denies you from reading about their delightful experiences at Applebee's. And it might lead to unpleasant repercussions down the road.
Remember too that adjusting one's privacy settings to exclude certain unsavory individuals is a perfectly acceptable approach if outright deletion seems too harsh. Such characters may include: those constantly fighting with their baby daddies, those who post pictures of their recently passed kidney stone, or those who are Andy Dick.
Social-media mistress Anna Pulley likes to give advice about how to play well with others on the internets. If you have a question about etiquette involving technology, shoot her a question at AskAnnaSF@gmail.com.