A negative example is that some people in the United States used the "unexpected news" of stocks to do "momentum trading", which ended tragically after a short period of glory. However, the "trend" cannot be underestimated. Buffett insisted on not investing in high-tech companies during the internet bubble, and as a result, he underperformed the market for several years. Perhaps only Buffett can survive such a bleak time. If it were anyone else, he would have died several times earlier. Looking back, it is understandable to watch the internet bubble coldly, but it is not worthy of respect to miss Microsoft, Dell and Yahoo.