The point
Say what the data supports.
Optimism and doubt are both easy. The job is knowing which one the numbers support, and saying so plainly, even when the story is charming and the room wants a yes.
The same discipline runs through my e-commerce work. See it in the case study.
The deal he walked away from
A founder brought me in weeks before signing an expensive franchise license for a boxing gym chain he planned to take to Saudi Arabia. I built the model and showed him the CAC and retention the fees demanded. Then I sat beside him on the diligence calls and took the franchisor's projections apart, including locations that were quietly closing.
He walked away. It's some of the best money he never spent.