In 1999, Antje Danielson wanted to start a car-sharing company. But she was a scientist, not a businesswoman, and she knew she couldn’t do it alone. After launching Zipcar with her friend Robin Chase, Danielson had to come to terms with one of her biggest mistakes: asking a close friend to become an equal partner in her company. Danielson tells host Ann Friedman what happened when Chase fired her, and why her choice to walk away ultimately saved the company.