If there's one thing that a start-up company has an abundance of, it's decisions that need to be made. The smaller and newer a company is, the fewer things are already defined which means that every little step in the process requires at least a little creativity.
I think that there are basically two different fundamental elements that can influence decision making at company: hope and fear.
If you are influenced mostly by hope, it means that you're driven by the idea of success. You have a vision of what you want to accomplish and you're willing to take the necessary risks to turn that vision into reality. It seems obvious that any successful entrepreneur must be driven by hope, because the entire process is an uphill battle and the only way to succeed is to do something disruptive.
Unfortunately, it's easy to let fear take over. Being motivated by fear basically means that rather than focusing on your goal of success, you're trying to prevent failure. This is an recipe for mediocrity.
There may be exceptions to this, but in general it seems like start-up companies are either successes, or failures. If you don't turn the company into something great, it will inevitably collapse. This is why I don't think it makes any sense to focus on preventing failure. Conservative decision-making is just a great way to delay the collapse, but it does little to actually prevent it.
I think that this philosophy probably applies to many situations other than entrepreneurship, but I have no doubt that it's the right approach for those of use trying to start something big. When faced with a decision, even a minor one, I always visualize tremendous success, and I act in whatever way seems most likely to realize that vision.