The AI sector has been in turmoil these past few days. Nvidia's GTC conference just ended, and AI-related cryptocurrencies have seen wild swings, while the US-listed optical communication sector has suffered a severe plunge. Many are bewildered: Nvidia was clearly talking about the future of AI, so why have related stocks collapsed? Let's discuss the reasons in light of the content of GTC: 1. Disappointing expectations are the main reason for this sell-off. The market previously regarded Nvidia as the godfather of optical communication, betting that he would announce the death of copper cables and a complete shift to optical. However, Nvidia was honest, saying they wanted both copper and optical, but the internal structure of the equipment racks would still be dominated by copper. This is a classic case of buying on expectations and selling on facts. Stock prices had already been driven to their ceiling, just waiting for an extremely positive announcement to trigger a surge, but reality didn't live up to the script. Those who bet on the wrong horse rushed out, naturally causing the collapse. 2. The market is weeding out the weak. The companies that suffered the most from the hype but lacked real performance were the ones with genuine technology, while those with real technological strength were more resilient. This shows the market has evolved; it's no longer blindly speculating on concepts, but focusing on practical applications and orders. This logic is similar to the cryptocurrency market. Previously, anything related to AI or RWA could propel a stock to new heights; now, everyone is watching protocol revenue. As the tide recedes, it's clear who's been swimming naked. 3. Don't fall into the time lag trap. The general direction of "lightning up, copper down" is correct, but the market is too hasty, mortgaging the next three years' growth in today's price chart. Technological implementation is slower than hype. Once expectations aren't met, valuations will plummet without hesitation. Correct logic doesn't guarantee correct timing. Using long-term logic to buy into short-term plays will likely result in losses on both sides. This GTC was a vivid lesson in expectation management. The market always wants to reach the sky in one step, but technology progresses step by step. Don't always try to rush into investing. Understanding the big picture and timing the market correctly are key to navigating bull and bear markets. When the wind stops, those who were flying high are the ones who suffer the most.