Appreciating the business: Investors often flow with the market sentiments and forget to take into account that what they are owing by way of investing in a stock. It is important to know the business before blindly investing in a stock.
Bear Phase: Most of the investors do the opposite of purchase when in a bear phase. This behaviour is a crowd habit, and successful investors do not include themselves in this category. According to great investor, Warren Buffett, an investor should not invest in a stock market until and unless he is prepared to watch his stocks value decline to half.
Paying too much: A stock when bought should be a good bargain. The stock buying activity should be similar to an Indian's habit of bargaining for the good price in groceries or vegetables. A stock if not purchased at the good price could become costly in the end.
Derivatives and Stock Trading: Investors who indulge in derivative trading or stock trading are deliberately driving themselves to losses. Investment has to be different from trading, where patience and discipline has a bigger role to play than anything else.
Making Mistakes: There is a thin line between being not stupid and very intelligent. An investor should learn to be not stupid rather than trying to act intelligent. Doing this will only save one from costly mistakes that accompany the behaviour of trying to be intelligent.