1) wrong valuation of company.2) inadequate mos or paying too high a price 3) failure to discern value from growth company. some companies might have features of both. But it is important to know n understand where the company fits in. 4) lack of patience to wait 5) premature liquidation when the best holding period for some companies is long term to forever. 6) trading mentality takes control of small profit while failing to stick to original plan. 7) buying into inconsistent or non dividend paying companies....