It is easy to talk about due diligence in the abstract, but it is much harder to practice what you preach. One of the hardest things about early stage investing is that it is really risky – if you don’t have some suspension of disbelief, and you obsess too much about cataloging every risk, you will never get a deal done. As a way of wrapping up this series of articles with a review, let’s take a look at a few common mistakes and see what we can learn from them.