Here are some of the most common investment mistakes, from emotional investment decisions to too much commission: 20 main mistakesDescription 1. Expecting too much Having reasonable return expectations helps investors maintain a long-term perspective without reacting emotionally. 2. Lack of investment goals Often investors focus on short-term profits or the latest investment fad instead of their long-term investment goals. 3. Lack of diversification Diversification prevents one stock from having a significant impact on the value of your portfolio. 4. Focus on...