According to the IRS:
Almost everything you own and use for personal purposes, pleasure or
investment is a capital asset.
When you sell a capital asset, the difference between the amount you
sell it for and your basis – which is usually what you paid for it –
is a capital gain or a capital loss.
You must report all capital gains.
You may deduct capital losses only on investment property, not on
property held for personal use.
Capital gains and losses are classified as long-term or short-term,
depending on how long you hold the property before you sell it. If you
hold it more than one year, your capital gain or loss is long-term. If
you hold it one year or less, your capital gain or loss is short-term.
So to answer your question, if that couch was purchased for your personal use, then you cannot deduct the loss. If you bought that couch for investment purposes, then you can deduct capital loss.
The difference between investment and personal property is what the intention was for. If you bought something with the intent to make money off of it, then that's considered an investment. However, if you:
you bought a cabin so you could get away on weekends. Although you
certainly wouldn't mind making a few bucks when it comes time to sell,
your primary motivation for the purchase was to have some family fun
and relaxation. This would make your vacation cabin personal-use
property rather than investment property.
In regards to cars and couches, if you bought a car with the intent to make a profit from it and fixed it up, etc. but ended up selling it for a loss, then you could claim that as capital loss.