We all know human beings aren't perfect - not even close. It is almost impossible for a person to be great at most things in life - we have our strengths and weaknesses - whether its in relationships, friendships, sports, communication, and of course in our work. Founders of startups are no exception.
We often say we are looking for "A+" founders or "Rock Stars". That is true - we want to back people who are great at what they do. Of course they need to meet the bar in ambition, intelligence, ability to execute, etc. But often times, its not a complete package - and certainly not early in their career if they happen to be a young founder like most internet entrepreneurs.
I've learned as a VC that one of the most important traits to look for in a founder is Self Awareness. This seems to separate the long term winners from the "flash in the pan" entrepreneur. Those founders that understand their weaknesses (whether its managing people, attention to detail, technical skills, negotiations, or softer issues like losing your temper easily, listening skills, etc) will be able to surround themselves with people and advice that will fill their gaps. I think its critical that a founder have a core "senior" team (ideally as co-founders) that compliment their skills and experiences. It leads to better decisions and checks and balances. Being self aware also means that a board rarely has to dictate leadership changes - the Self Aware founder reaches the conclusion well before others and recommends the best course of action for the company.
How do you know if you are self aware? Simply write down your personal pros and cons and then ask for a 360 degree of the people that work above, below, and around you to talk about your strengths and weaknesses. See if you truly know how others perceive you. I've done these 360s for myself in every job and its been eye opening and helped me go to the next level.
Founders need to be a lot of things to make a venture successful - but we don't expect them to be perfect - just be Self Aware...