Investing in Apple Inc. has been described as a challenging experience, particularly for long-term shareholders. Callie Abost highlighted that a $1,000 investment at Apple's IPO would be worth nearly $2 million today. However, she noted the emotional toll of holding the stock over two decades, which included eight instances of the stock dropping by 50% or more and the company experiencing three CEO changes within four years. This volatility and uncertainty have made the process akin to 'mental torture' for many investors, who may find themselves unable to enjoy the substantial gains on paper. Ritholtz Wealth Management echoed this sentiment, emphasizing that the long-term strategy of buying and holding a single stock can lead to unique psychological challenges, with many investors not fully appreciating their paper profits.