There are many types of fear, fear of the unknown, fear of what others think, one of the biggest reason people do not walk in their purpose is due to fear.
Some people have been told their whole life that they would never amount to anything. Some people have tried to do something and failed at it and have become discouraged. Other's have compared themselves to peers and that has led them to discouragement.
3.) Capability ( People feel like they are not capable of walking in their purpose)
A person that feels like they are not capable probably feels like God has not called them to do anything and if He has they do not understand why. There are several reasons why someone would feel like they are not capable.
4.) Feelings of Unworthiness
A person who feels like they are unworthy may be full of guilt or cannot see why God would want to use them after all they have done.They also may feel like they cannot help others because they are dealing with so much themselves.
* If this is you, know that God loves you and He will use anybody that is willing*
5.) Purpose Unknown
Sometimes people just simply do not know their purpose, it doesn't mean that they do not want to know. It just has not stood out to them yet.
Some people are content and haven't further thought about their God-given purpose. For some the thought of fulfilling their purpose may mean that they have to give up something that they are not yet ready to give up.
7.) Time Frames
Sometimes we develop a time line for how we want our life to pan out, while forgetting that God has a plan. God's plan trumps our plan and it usually is always better than what we had originally planned. Sometimes we lose focus on what God wants when things do not happen in our time frame.
8.) Bigger Requirements
This also kind of goes along with contentment. When we begin to think of God's purpose for our lives we start to think about requirements. We form a list of do's and don't in our heads that ultimately lead to can and cannot's. Some people feel following their purpose has bigger requirements that they have not met yet.
*Key thing to remember here is that God qualifies those that He calls, He will prepare you for what He wants you to do*.
9.) Lack of faith
This one here is a biggie,we know that faith is everything! Some people do not believe in themselves.
People do not know who or where to turn to. Keep in mind that sometimes your purpose could have to do with business, family, it could be any area of your life. Some people do not know how to get started. For instance, if God tells someone to start a youth center and they know absolutely nothing about about starting a business, they may not do it due to lack of resources. Same thing goes for if God tells them to write a book, it could be a lack if resources that causes them not to do or be delayed in doing it.