In his book, The Unspeakable: And Other Subjects of Discussion, Meghan Daum said that comfort zones can be places of great satisfaction - as long as we are effective in them. "The key to satisfaction is to live life fully within the limits of your comfort zone," he wrote. "Stay in safe water, but enter as close as possible to it. If you are good at something, do it a lot. If you are bad at something, don't do it."

Relationship expert and clinical social worker Debbi Carberry agrees that we can "shine brightly" in the comfort zone. And our relationship can develop in it too. "The comfort zone means security, satisfaction, connection and predictability," he said. "All that the human brain likes."

So why is the perception that our relationship is more likely to fail than to hiss as soon as they enter the comfort zone? "The problem is comfort is confusing with the real relationship of complacency, indifference and release," Carberry said. "This is when someone comes through the front door and doesn't talk to you, but sits on the sofa and waits for dinner. It's not someone who feels comfortable. It's someone who shows that they don't care."

The workplace - in the midst of a choir of advice on how to progress and make an impact - is another arena for considering comfort zones. Andy Molinsky, professor of organizational behavior at Brandeis University, spent a year talking to workers about the comfort zone for his book, Reach: A New Strategy to Help You Step Out of Your Comfort Zone.

Although Reach generally encourages readers to leave their comfort zones, Molinsky also says we can achieve career success by staying afloat. "There are times when you don't actually need to give a speech, convey an intention, or take a chance," he wrote in the Harvard Business Review.

Molinsky says we just have to get out of our comfort zone for something we really care about, not because of external influences or peers making us feel that we should. And he added that if we have a view that makes us feel comfortable with new skills, such as improving speaking skills or public networks, we need to commit to mastering it. "If you don't have time to fully prepare and follow up, it's not worth going forward."

Meanwhile, if we want to move forward in front of fitness, a common motivational mantra like "Push harder!" "Without limit!" and "Enjoy the pain!" center on embracing discomfort.

But signing up for the latest program that promises to push your body and mind outside your comfort zone will not work for everyone, said Ashlee Chandler's personal trainer and fitness instructor. "If you feel uncomfortable doing the exercise, or the program will take more time and money than you have, you can risk stopping together," he said. "You can still get results with programs that are consistent and effective in your comfort zone."