I have shared this Harvard Business Review article far and wide, for years: in my opinion hiring slow, and firing fast is the MOST IMPACTFUL team-building activity you can undertake, when needing to establish a cohesive team in any startup or high-performing group.
And in the interest of equal-time, here is a counterpoint to the above, which I enjoyed reading even though I didn't 100% agree (never just go for the confirmation bias, y'know!).