I think it has to do with intrinsic value- what is (thing) worth beyond what people are willing to pay for it? Many companies aren't worth the price on the stock market, a phenomenon known as overvaluing. Warren Buffett himself has claimed Berkshire is overvalued; relative to its book value, he's right. Class A stock has book value of $320,155.60/share, meaning Class B should be worth $213.44/share (thanks to a a 50 to 1 split, Class B is worth 1/1500 of Class A).
Back to intrinsic value: if you don't know the value of what you're investing in, the only thing you have to go by is price. Since price in the stock market is, in general, hysteria-driven groupthink, if you don't know the value of your investment, you'll inevitably be panicked by what is essentially other people's judgement. Incidentally, this is the heart of technical analysis: use proven patterns of behavior to guess how traders will think. This is also why technical analysis fails in times of volatility: black swan events and uncertainty from Trump's latest edicts can throw your funny graph patterns out of whack.
An example of intrinsic value is your house. Do you check its value on Zillow daily? No, of course not. You're only concerned when you need to sell, because you know the house has and will retain value. It's the same with precious metals. We know the value of what we hold, so we have no reason to panic over a red day.
A good test to see if you know the intrinsic value of what you want to invest in is this: if you invested in it, but were not allowed to check the price or sell for the next five years, would you? If the answer is "no," you have no reason to place your money in it.
I would urge the stock market thread to read up on Ben Graham's parable of
Mr. Market. Once you understand the value of what you hold, the price of your investment (stock, crypto, etc.) will no longer panic you.