There is a place that people who want to be successful must go through. Of course "success" is relative. But if you want to grow, expand and achieve bigger goals or seek change, you must go through "there". What is "there"? That space between where you are currently and where you want to be.
Many people have opened that door or stuck their toe in it only to pull back. They found that the stress, discomfort or uncertainty of progress is too much to bare. So they pull back and accept. They stay at their current level of achievement.
If you want to be successful, if you want growth, you MUST go into uncomfortable and uncharted waters. It is normal to feel challenged when striving. Otherwise, you are just staying in your comfort zone and going nowhere.