Please don’t ever estimate the importance of startup founder compatibility. It’s vital. And it may not be what you think.
The relationship among founders of a healthy business is like a marriage. Compatible goals, thinking, values, and decision-making styles is really important. Even if a well-run and successful business, there will be a lot of times when disagreements come up and compromise is necessary.
To start at the beginning with people who don’t agree on the very fundamentals of the business is a bad idea. It’s a recipe for a painful failure.
On the other hand, don’t confuse compatibility with sameness. It takes a mix of different skills and backgrounds to build a business right. Somebody has to mind the money and administration, and somebody has to create the product, somebody has to build it (or deliver the service), somebody has to get the work out, and somebody has to close the sales. You want complementary skill sets and backgrounds and expertise, not everybody all alike. And that, by the way, does support diversity. In genders, backgrounds, ethnicity, and other factors.