Psychologists have theorised that there seems to be in the human psyche an irrational fear of unrealised loss.
The reality is that one only realises a profit or a loss when something is actually sold.
In any speculative venture, managing to sell a tradeable asset at the highest market value/price point
is likely to be largely a matter of chance. If one sells it at a profit, then, however one might attempt (and fail) to predict it, the market's perceived value of the asset could subsequently (of course) go down as well as up, post-sale.
However, if the asset was sold at an acceptable profit at the time, then, from an accounting perspective, it was a profitable investment, by definition. Barring fraud or market-rigging, the fact that the asset might have risen appreciably in market value after
having been sold is kinda academic, and to consider its rise in value as, for example (say) a missed opportunity, or as a loss/cost, because the higher resale price was never realised, is a speculator's (gambler's) irrational nightmare.
It's an "If only I had a done such-and-such" event - a sort of needless self-recrimination, post fact
One would arguably need to hoard and avoid selling any
tradeable asset - once acquired - if one wanted to be sure of getting the highest possible potential future sale price, and thus one would never actually sell, and the objective would be forever unachievable, and the price would continue to fluctuate up or down, regardless. The unsold/hoarded tradeable asset would simply form part of one's estate on death.
A useful rule-of-thumb is probably:
Buy when everyone else is selling and hold until everyone else is buying. That's not just a catchy slogan. It's the very essence of successful investing.
- J. PAUL GETTY.
I recall reading another another quote from Getty to the effect that:
"To avoid taxes, in life have all capital but no income; in death have all income but no capital."