When is it too cold?

I'd like to think that we all know our limits.  But, really, how much can one person take or withstand?  When things get hard we all have different ways of coping or managing the issue.  Some people shut down, while other people get fired up.  The determination and drive to live in some people is incomprehensible to some.  There are some people that have so much resilience that they don't ever think of giving up.  

What would it take to push yourself to conquer your dreams, overcome your biggest obstacles, and live a better life that you have only imagined.