Just prior to pitching to an angel group, an entrepreneur I know got feedback from one of the angels that he might want to reduce his forecast numbers, because they seemed too aggressive to be credible. So what does an entrepreneur do in such a situation?
The challenge, of course, is that different investors will give you different feedback, and you don't necessarily want to change your forecast (or other aspects of your business model) based on the feedback from one investor. The next investor might provide the opposite feedback!
In terms of financial forecasts, in reality, no sane investor will believe that your numbers are right. Your challenge is to convince them the those numbers "could happen", and that your team has a credible chance of making those numbers happen.