Just kidding. Of course there's room for doubt, most things are in question at startups. We're "under conditions of extreme uncertainty."
However, there should be absolutely no room for doubt when you're talking/pitching to: investors, potential customers, employees, business partners, and journalists. People feel even the slightest form of uncertainty. And then they stop believing in your team.
Here's the story behind this:
We had some shaky 2 months with SHNUPS, with a lot of conceptual stuff being in question (including our name and vision, more on that later). We tried to act confidently, but noticed that people reacted towards us differently: our uncertainty had a negative effect on how people perceived us as a team, and how they thought of our product. It was almost impossible to excite people for our idea.
Now we're back and 2016 already had some great successes, with amazing features to come within the next 2 weeks. This whole excitement completely changed how we talk to people. Now there's no doubt we believe that we're building something great, which is definitely noticed. Feels great!
Enjoy your week!