I was on a local sale page once.
I offered something for sale, then a day before the buyer was due to collect, changed my mind as I still had urgent use for the item. I then put it on eBay a week or so later after I'd used it.
Because I pulled out and then put it on eBay, she began a hate campaign -starting with the page admin (her real life friend) calling me a con artist, gradually her other friends got involved on the page, and inevitably Chinese whispers ensued, which ended up me being branded a 'babykiller' as one person insisted I'd been private messaging I'd murder their children
and so the next person dropped their jaw and pretended they had too. It was a bizarre group catalyst situation, and to this day I'm still shocked at the ferocity of it all.
It still goes on too (of course I've been banned from every single local sale page after she contacted all the admins) and I've seen the same thing happen to other people on her page.
The funny thing is, I had stood next to her at the school gates for a year, doing the usual chat about the weather and don't the Reception kids look too small for school yet. We've even shared an umbrella in the rain, yet she had no idea I was the same woman she'd shot down as a 'babykiller' online. Amazing how your online character can be so different from your real life one. I liked her in real life, she was sweet.
There's something about the virtually total anonymity of eBay that makes trading a pleasure though. eBayers are far more friendly and polite.
Facebook selling is full of a disheartening number of people who can't spell, and are up for a bunfight at the drop of a consonant!