Business with friends and family

So these is a tricky one, there are tons of family business, a lot of theme are successful, same with friends, people decided to innovate so with a few friends they create a company and oh boy company goes big.

I personally think starting a business with family or friends is something pretty delicate, there has to be mutual trust, boundaries, and a lot of seriousness, and not everyone would do it for a lot of reasons

Would you do it? what would be your requirements, what would you do if a familiar or a friend comes with an idea?, and how would you handle it, including worst case scenario when everything goes to hell? I would like to know