If you're in a "selling stock" part of your life I understand, but if you're in a "buying stock" part of your life it's worth reflecting on the quote until you can shake the "recent price action IS investor psychology" out of your head.
Even when people are only buying with no intent to sell, they'll often complain if prices fall right after they've bought an item, and ask for a rebate for the difference, because they feel they deserve the new lower price. Many retailers are aware of this psychology and do offer some sort of forward-looking price match, both to help buyers overcome that hesitation, and to avoid going through the paperwork of returning and refunding a used item just to sell the same thing again anyway. But the stock market offers no such buyer protections.
It's not a flaw for people to think from the seller's perspective. For you to be a net buyer, someone else has to be a net seller.
Not to mention the unhappiest of all: the people who borrowed money against the value of the assets they owned.
In some situations you can deduct losses in the stock market from the taxes to pay over the next 5 years. Not the same, but not nothing.