Emotion - it's a savvy investors worst enemy, let it seep into your decision making and you're going to end up hurt. Emotion and misplaced faith in a company are what lost me 100% of my investment. So far my worst investment yet. It was about a year into my dabbling in the stock market, so far I had purchased only large NZX50 companies such as Summerset, Air New Zealand, and Chorus. They all turned out to be solid investments and reasonably safe.