Being comfortable is soothing and provides a certain level of peace and calmness. This feeling of fitting right in and being in the right place at the right time. But that state of mind can also pose a danger. Getting too comfortable with your current situation will cloak you in a false sense of security when you should be alert. It will make you feel relaxed when you should be on your toes and on snooze-mode when your alarm should be going off.
Comfort is good because when we feel comfortable it is easier to blossom in a particular environment. It will provide that additional flavor of self-confidence needed to dare maybe only tiptoeing a bit outside of your comfort zone. Not too much though, just enough to remain comfortable where you are. But there is also a state of being too comfortable. That state when you transition from developing, increasing, and moving forward to a place of "comfortable stagnation". A place you will hardly even notice you are in because things are good, everything is going well, you have found your routine = you are comfortable!
Why is that a problem? Because life is a race. If you have watched sport's games or competitions you will see that there is constant movement. The ones sitting on the sidelines are on timeout and are eager to get in the game. It is the same with life. The ultimate goal should not be settling for less because you are finally comfortable where you are but always striving for more. "Do you not know that in a race all the runners run, but only one gets the prize? Run in such a way as to get the prize. Everyone who competes in the games goes into strict training. They do it to get a crown that will not last, but we do it to get a crown that will last forever. Therefore I do not run like someone running aimlessly; I do not fight like a boxer beating the air. No, I strike a blow to my body and make it my slave so that after I have preached to others, I myself will not be disqualified for the prize." 1 Corinthians 9:24-27 NIV
Also, think about the reason why people don't want to step out of their comfort zone - fear! The fear of facing opposition, problems and having to struggle. That is where many people get it wrong. Stepping out of your comfort zone does not equal stepping into your "struggle zone". If you have the desire to do more and achieve more you will have to take that extra step that will probably challenge you but most importantly help you to grow as a person. And it will require that additional portion of faith to move forward.
Discomfort is exactly that: uncomfortable. But that is what you need to push yourself towards reaching the next level in your life. Staying exactly where you are might seem like the safest and more comfortable option but there will be a time when even that spot will not be conducive for you anymore. If you want more, then you have to do more!