Open to change
A few days back, Paul Graham found a basic quality of good startup founders: Be relentlessly resourceful. Really, a beautiful definition. Think about it, one of the most important qualities required in starting up is the will to accept change and adapt to it in every possible way. You can never work the same way tomorrow as you did today. When starting up, every single variable would change between now and 5 minutes later. Today, if you are a php coder, tomorrow you are a graphic designer. Today if you are meeting CEOs in luxurious hotels, tomorrow you are doing sales and marketing in dusty streets. Today if you are reading about switched mode power supply systems, tomorrow you are learning the basics of value added tax!
Startups are inherently risky. You never really know whether the idea in your head is a good one until it tastes success. The only way to know is by actually starting. Change is the only constant in startups. The enormity of the number of changes and the lack of time to adapt to those changes can only be experienced to be understood. If you are one of those who thinks change is what you need in life, then start something today.