PEAK6 Investments' Matt Hulsizer reveals the single most important trait for a successful CEO: "The number one thing we've learned, because we've dealt with thousands of employees and CEOs, is that self-awareness is probably the most important thing, because without it you can get in trouble." "You control effort, you control attitude. But awareness... CEOs need to constantly question where they're at and be humble." "And I wouldn't say lack of confidence is necessarily an issue, but…