Life begins and ends with your Comfort Zone!

I just read that and it really made me think.  I've been coming across that a lot lately in my own life.  Dealing with being an introvert in a job that has a lot of people coming and going in it.  Having a second job I dislike but am scared to leave it because it's security, yet knowing I need to spend my time elsewhere.  All these things come down to our comfort zone.  This next month I want to try and push that comfort zone.  Stretch those muscles.  I'm fairly good with change at times and at times I just like to sit on that big couch in the comfort zone.  So maybe I need to see how uncomfortable that couch is.
What's your experience?  Do you live in the comfort zone?  Does your life end there?