Common trading errors include following the crowd blindly, a lack of independent thinking among investors, hastily trading based on market trends, and getting caught at high points. There is also overtrading, driven by emotions, resulting in frequent buying and selling, which increases transaction costs and can lead to losing direction. Moreover, there is a lack of stop-loss awareness; when market trends contradict expectations, unwillingness to cut losses can lead to larger losses. Additionally, greed and fear often dominate decision-making, such as being greedy and not taking profits when in the black, or panicking and cutting losses when in the red. These mistakes can all impact trading returns.