It seems to me that you might have begun to over-construct your characters (and maybe other parts of your narrative as well).

Many aspiring writers look for rules and guidelines in how-to books or on the internet and attempt to apply those principles in a very rational manner. As a consequence, they have no emotional connection to the characters and plot that they assemble.

This is what you experience. Your protagonist is meaningless to you beyond the fact that you have defined her as your protagonist.

What you need to do is to begin with a protagonist that you care about. Create her in the way that you feel most strongly for her.

Many writers put (a part of) themselves into their protagonists. Their heroes are their alter egos: who they are or who they want to be or who they are afraid to be. Other writers write about characters that they desire: the men and women they want as lovers or friends or in some other capacity in their lives.

If you have a character like that, a character that you deeply care for, then it no longer matters whether or not other characters are more "interesting". There are many persons more interesting than myself, and yet I would never write a novel about them, because it does not really interest me how they live their lives and do what they do.

What makes good books exciting and intriguing is the emotional investment of the author in their protagonist. That is what makes a fictional hero come alife.

I always like to compare writing to drawing. If you stupidly follow some schema of human proportions, your drawing will look technical and dead. But if you forget about the rules and just draw what you see, then the proportions of your figure may be off, but your linework will be vigorous and alife.

Mastery, of course, achieves both perfect structure and vivid emotionality, but I have found that as a consumer I value emotion over perfection and as an artist I manage structure best subconsciously and "from the gut".

It seems to me that you might have begun to over-construct your characters (and maybe other parts of your narrative as well).

Many aspiring writers look for rules and guidelines in how-to books or on the internet and attempt to apply those principles in a very rational manner. As a consequence, they have no emotional connection to the characters and plot that they assemble.

This is what you experience. Your protagonist is meaningless to you beyond the fact that you have defined her as your protagonist.

What you need to do is to begin with a protagonist that you care about. Create her in the way that you feel most strongly for her.

Many writers put (a part of) themselves into their protagonists. Their heroes are their alter egos: who they are or who they want to be or who they are afraid to be. Other writers write about characters that they desire: the men and women they want as lovers or friends or in some other capacity in their lives.

If you have a character like that, a character that you deeply care for, then it no longer matters whether or not other characters are more "interesting". There are many persons more interesting than myself, and yet I would never write a novel about them, because it does not really interest me how they live their lives and do what they do.

What makes good books exciting and intriguing is the emotional investment of the author in their protagonist. That is what makes a fictional hero come alive.

I always like to compare writing to drawing. If you stupidly follow some schema of human proportions, your drawing will look technical and dead. But if you forget about the rules and just draw what you see, then the proportions of your figure may be off, but your linework will be vigorous and alive.

Mastery, of course, achieves both perfect structure and vivid emotionality, but I have found that as a consumer I value emotion over perfection and as an artist I manage structure best subconsciously and "from the gut".