Good leadership is about continuously looking for things that could be improved upon, says Sunny Gupta, CEO of Apptio. The "glass half-empty" approach isn't pessimistic as much as it's realistic and ambitious, Gupta said. "Every single day, maybe 85% of things are going right, and there are 15% that aren't going right," he said. "... I'd rather focus on the 15% that are not going right, because that's how you become great."