Sooner or later, you will have employees, a Board of Directors and perhaps investors. You will also have customers.
Everyone has an ego. Some people will force their egos into the relationship for reasons that are incomprehensible. And firing them is not always the answer or even possible.
The challenge is to figure out how to use a person’s ego to get the value of what they have to offer. Channel them into roles where their ego is an advantage. Isolate them from circumstances when their personality is detrimental.
If a board member is prone to outbursts during a board meeting, meet them for coffee ahead of time and preview the issues with them to gauge their reaction. If it’s going to be negative, you’ll know and they won’t hear it for the first time. On the positive side, this person will help you sell your idea if you include them in the conception of the idea (make it theirs).