In this image I have placed the egg in center of the frame but is it really not visually interesting? The answer is yours since it is going to be subjective. I think dividing the entire frame using shapes of circles helps the viewers eyes to recognize the subject with an ease (Ref: Gestalt Law of grouping). So the egg in the centered portion doesn't matter to much, in fact it is catching the viewers attention without loosing interest. If the subject was only egg then there will be enough space to divert viewers eye in entire frame.
A centered subject can also be made interesting by using virtual lines leading to the subject. It will avoid the viewers eye to wondering everywhere unnecessarily while guiding it to the subject of interest. Image 2. is an example illustrating this.