Stock investors are having a hard time. The widely followed S&P 500 Index of US stocks peeped above 4,800 in early January and recently fell below 4,000. Even more painfully, the technology-heavy Nasdaq 100 has fallen from above 16,500 to below 12,000, and many individual stocks have suffered much bigger losses. As ever when stock prices fall, the usual flow of narrative and prediction has swelled to a flood. Anecdotally, various combinations of inflation, interest rate, growth and war worries are the favoured explanations this time.  Importantly, the often emotionally driven decision-making of such periods can prove very damaging to…