My son, who is two and a half, has this program he likes on the computer. He has used it for a long time and in fact it helped to teach him his ABC's about a year ago. Since then he occasionally goes back to the computer and brings it up so he can play. It has several different areas like learning to read, spelling, etc.. He always just wants to do the ABC's. You know why? Because it is easy and comfortable. I told him that if he doesn't challenge himself that he will never reach his full potential. Yep, I got the sort of vacant stare that you would expect to get from someone his age but the point is valid.
Photography can be looked at in this same way. I used to shoot nature and wildlife exclusively. Why? Well, I was comfortable with that. I knew what to expect, I didn't really have to interact with people, and no one was expecting anything from me. It was safe. I have stepped out of that comfort zone and found that I truly enjoy photographing people in different situations because each one poses it's own unique challenges. I am a better photographer because I allow myself to be challenged.