Since starting to learn a little about writing I've noticed that I'm more critical when I read things. This has led to a conundrum I've had recently and I'm not sure if it's inevitable or the result of 'bad' story telling.
The problem is that when reading a novel I often times identify and invest in the 'wrong' character. By that I mean I'm more interested in one of the side characters than the protagonist and this leads me to not really enjoying the story. Not because the story is necessarily bad but it's become not the story I wanted to unfold.
I'm not sure if this is because I'm now reading things in a different way and asking myself questions about character motivation and development during reading. I'm not sure if this is because my imagination is starting to work on developing a story other than the one the author intended. I'm not sure if this is happening because the author is failing to tell an engaging enough story in the first place.
The best example I can quote is from a fantasy novel in which the young hero is being mentored in his early years by a veteran mercenary and a scholar. The idea is that the hero's formative years are full of lessons in both warfare and politics. My problem is that both of these characters seem to have more depth to them than the hero. I care more about them than the hero. I'm interested more in their story than the one that is being told in the book about the hero.
I've not finished the book yet. I am at the part where for, reasons, both of these mentor characters are no longer in it. I suspect that the hero will now be placed in a position to make decisions and face choices based on their teachings but I'm not sure I can be bothered to find out. I don't really care that much what happens to the hero now those interesting characters are gone.
To turn this into a question. Is this a fault of some sort in the story or the writing of the author? Is it usual that some of a books audience will become more invested in a side character than the main one simply because of personal bias?
EDIT: I wanted to add something after selecting my answer. That is because the one I selected most directly applies to me however I would urge anyone reading this now to look at all the answers as they do contain interesting information. I don't really feel like selecting just one does the others justice. I'm now of the opinion that there will always be a few people that identify with the 'wrong' character from the point of view of the author. It's only a real problem if most people do that. Even then the author may be more interested in telling the story they want to tell rather than making the work more popular. That decision is theirs alone to make.