One of the classic venture pitch mistakes is overselling. Overselling your idea can take many forms, but one of the more humorous occurs when the entrepreneur shows you a set of projections that are wildly optimistic and then drops the G-Bomb as a way to claim that the projections are actually quite realistic bordering on being conservative. The entrepreneur will usually say something like: "Our business has many similarities to Google, so we took an X% discount to their growth rate and plugged it in to our model. We were conservative in taking the discount so we think our model is actually conservative." Really? And you're going to build your plan around that?
I've had the G-Bomb dropped in relation to startups doing ad-networks, the semantic web, and vertical search when that was all the rage. Today I'm seeing a switch to entrepreneurs using the F-Bomb for startups in the social networking or social shopping markets. Unless you're already at a point where you are seeing never-before-seen leading indicators, don't do it. And even if you are seeing something special, remember, a venture capitalist's job is to connect the dots and your job is to bring them close together. Putting wildly optimistic projections into your plan doesn't help me connect the dots to an enormous outcome, it causes me to question whether your feet are planted firmly on the ground or not.
Every few years Silicon Valley mints one of those iconic companies that defines a category and rides a growth trajectory that has never been seen before. It's part of what makes the valley so great. It's a great thing to believe that your startup has that potential. But there is a big difference between selling the dream and setting a realistic and achievable plan for your startup. If you build a culture around lofty unachievable expectations then you're going to have a very difficult time making it through the ugly adolescence that most good companies go through.