It's not whether the glass is half empty or half full, it's who is pouring the water. The key in business and success at any endeavor is doing your best to control your destiny. You can't always do it, but you have to take every opportunity you can to be as prepared as-and ahead of-the competition as you possibly can be.
Mark CubanHaving the ability to be brutally honest with yourself is the greatest challenge you face when creating a business model. Too often we oversell ourselves on the quality of the idea, service, or product. We don't provide an honest assessment of how we fit in the market, why customers will buy from us, and at what price.
Mark Cuban