Why is passion so important to a startup?

You hear investors and start up gurus talk all the time about the importance of entrepreneurial passion but I haven't seen anyone talk about why it's so important. It's almost as if everyone thinks the answer is self-evident. In my role at Founder's Co-op, I'm seeing multiple companies at the same stage struggle and think I have identified some (by no means all) of the reasons passion is so critical to a startup founding team. Passion gives founders :

  1. The ability to continually motivate and re-invent: By definition, founder's don't have all the answers. They are in a learning mode. They are learning what customers wants, how they're going to charge, how they'll scale, etc.  They are often crude implementations of what they aspire to be and as such, founders inevitably will have to overcome rough patches and patches where they don't know what the right answer is. Enter passion. Passion makes overcoming this lack of answers possible and fun. 
  2. The willingness to work longer hours than the average person. 
  3. The energy to sell customers, employees, and investors possible. It allows you to overcome all the "no's" you'll hear day in and day out. 
  4. The will to take feedback on limitations of yourself and your corporation and actually do something about it. 
  5. The desire to persevere and persist when the going gets tough.  

In a nutshell, passion is the word people use to attach to all the emotional aspects of founding a team that require energy, inventiveness, fun to overcome.