Everybody likes a comfort zone because it's safe and easy. But when it comes to business the most successful people intentionally seek out situations that are unfamiliar, stretching or uncertain. Take it from Ellen Rubin, CEO and cofounder of ClearSky, a Boston tech startup currently in stealth mode. Prior to ClearSky she was vice president of marketing for the data warehousing company Netezza, helping to lead it through an IPO before it sold to IBM for nearly $2 billion in 2010. She also cofounded CloudSwitch--a company that made it simple to connect to a data center and public cloud--which was acquired by Verizon the following year. The secret to her success? Starting companies focused on tech that's not her expertise. While you might think it would be easier for her to stick with subject matter she knows well, Rubin says getting out of her comfort zone has several benefits.

Here's her rationale.

1. Experts can be too skeptical.

When you've been working on a particular area of focus for years you can be overly quick to see all of the things that aren't going to work. You may also tend to think about solving problems via methods you've used before. "Honestly, as an entrepreneur that can often be a big mistake," she says. "It can be very limiting because it will either lead you into a direction that's very incremental on top of what's already being done today or it will blind you to things that could be a little crazy but more exciting and more disruptive."

2. Expertise can lead to entrepreneurial fatigue.

When you know a space well it can be overwhelming to think about the immense list of to-dos that will be required to launch a company. So instead of thinking about all the missing parts that need to go into maturing your product, just limit yourself to figuring out one thing: How you're going to solve one huge pain point for customers in a way that no one thought possible. "Let me just focus on that and nothing else and it livens you back up again," she says.

3. Without risk-taking a startup won't succeed.

Whereas a large company can offer customers safety and security, a startup's strength is in its ability to be nimble and agile and solve difficult problems in unique ways. "The minute you find yourself saying 'We're going to go with the same obvious choice' the risks are so high in terms of what you're doing becoming not breakthrough enough, not exciting enough, not making a big enough difference for your customers," she says.

4. The most successful people within a startup are the risk-takers.

At the critical pivot points in a company's life these people drive decision-making and encourage the company to reach for difficult things. "You never wonder in a small company who the superstars are," she says. It's very clear to see them because they're the ones coming in every day and going 'OK, how are we going to do this? What are we going to do?' They're really pushing the thinking forward."