Poor coordination across departments. The Dilbert effect has killed many companies. Don't let it kill yours. Show up at a demo, sales call, trade show, or meeting unprepared. Preparation is the key to a successful demo, sales call, or the like.
Time is precious.
If you go into a meeting unprepared, you will waste everyone's time, and loose the respect of the people you are meeting with. Ignore the competition, they are far inferior to us. Unless you know your competition's strengths and weaknesses, you will never know how to beat them. Just as important is to know whom your competition truly is. Miss deadlines that we commit to internally and externally.