If you are used to having to answer to someone else for your behavior, you are less likely to develop your own conscience as your internal guide. That external voice, the one you feel a need to please, speaks in a louder volume. It blocks the sound of your inner 'still small voice'; it might speak to you in a demanding or fear-inducing tone.
By comparison, your true inner voice connects to a higher level of your spirit. The tone is calm. You experience its guidance as firm and loving. It induces within you confidence and connects you with to God with awe.
In the course of our lifelong growth process, we are challenged to gradually replace the external voice with our own inner voice to make it our compass and help us make good choices. This is the development of true conscience.