One thing that holds us back is fear. This is probably the main one. Fear always hinders us from stepping out into the fulness of what God has for us. Fear will cause us to fail. Fear causes us to be disobedient.
Fear is the opposite of faith.
Combat fear with faith. We must press on to know Him more and hunger for all that He has for us. We cannot afford to pick and choose which gifts we want operating in our lives. We must allow the Holy Spirit to distribute His gifts according to His will. Please read the other teachings on the Gifts of the Holy Spirit on this site.