It is advised for Nvidia employees with more than 90% of their net worth or over a million dollars in the company to sell their stock to diversify and mitigate potential losses. While the stock might double, the risk of an 80% decline outweighs the joy of further gains. Loss aversion theory suggests securing a win by taking most profits off the table and hoping to be wrong. It is crucial not to fall into the trap of overconfidence or emotional attachment to the company, but rather prioritize financial security and prudence by diversifying investments and avoiding high concentration in a single asset.