One of my pet hates is seeing people selling stuff second hand, but including the original price on the ad.
THAT to me, is CF.
Sofa bought last year for £2,600.
Will accept £2,300.
Ladies jacket bought for £60.
Will accept £55.
Will ye now?
I don't think that's at all unreasonable, as long as there's a sizeable price differential e.g. '"Jacket bought for £60, worn for one evening only, will accept £25". I wonder if some do it ready to stave off the CFs who will otherwise claim they know the new price, that just so happens to be the same as you're asking for a used one. The only problem there, though, is that the jacket may well have cost you £60, when it first went on sale, but the shop might have sold off the last of their end-of-season stock at 50% off; so even if you're telling the truth, the fact that the would-be buyer has seen it more recently at £30 makes them think you're lying.
I do agree it's very cheeky when people expect 90-95% of their purchase price back when they've used something. They only think of their own pov and how much they're 'losing' for an item that's still in excellent condition (not really, as they've had the use of it); but if they could only think from the pov of a stranger, who in their right mind would pay £75 when they could get a brand new one, maybe with guarantee - which they can return if faulty - and free delivery to their door, for £90?
I'm not going to use the 'narc' word, but I do think it's endemic that so many adults can only see things from their own pov. Also, some of the buyers see what they want for sale, decide that 'they'll take it' and then naturally want it for the lowest possible price, ideally delivered free. They disregard distance because that's simply where they live, so it will obviously 'need' to be delivered there. They don't actually compute that there's a real person behind it - a stranger, who wasn't desperate for them to have it regardless, right from the start - even before they actually knew of their existence - whose time is equally precious and who, quite reasonably, actually wants to earn some money in exchange for giving up their quality item.
That said, I wonder if a lot of modern buyers' expectations are skewed by the fact that you can buy so many new items on eBay, delivered free - even cheap and/or really heavy stuff. They realise that private buyers selling used stuff should expect to receive a lot less than a shop does, but don't seem to comprehend that the shop is selling at volume and gets a great commercial deal for mass delivery of thousands of items - that courier does it all day as their paid job and will have lots of other deliveries in your locality to make the 'machine' cost-effective, it's not the same as expecting a random person to give up hours of their free time and pay for the fuel for the round-trip to take one item across three counties.