There are a lot of characters in this novel, and going over the internal conflicts of each could very well be a novel in its own right. I'll pick a few characters.
Mr. Tulliver is a good starting place. He is a man who is constantly trying to figure out the puzzles of the world. He would do great with it, too, if the novel took place 100 years earlier. The problem for Mr. Tulliver is that the world is modernizing faster than he can mentally keep up with. He works hard, saves his money, and grows his wealth slowly. He is completely incapable of understanding the new venture capitalism that is emerging around him. Mr. Tulliver is old school. Business is done through interpersonal relationships. His flawed logic within the new business structure is what causes Mr. Tulliver to see enemies that don't really exist. In the end he is consumed with anger, bitterness, and regret.
Tom Tulliver is another conflicted character. His internal conflict, though, is a far cry from his father's world puzzling. Tom's conflict is that he sees the world as way too black and white. He has a huge sense of justice and right and wrong. That's not a problem in and of itself, but Tom doesn't ever seem to point that lens back at himself. His attitude pushes people away from him. He's not a compassionate or empathetic character to begin with, so as people distance themselves from him, Tom becomes more cold and harsh and less and less compassionate. His sense of justice and high work ethic are positive traits , so Tom isn't a bad guy in the novel. He is a very frustrated character, though, because in his mind he is doing everything right, but people still don't like him.
Philip Wakem is just as conflicted as Tom, but in the opposite way. First, he has a physical deformity, so people already are cold and distant from him. Next, he is a very intelligent and well read individual. Additionally he is a very compassionate character. Sounds great, but none of the above description translates into a "manly" stereotype, which may be a reason a relationship with Maggie is never considered. He's an odd character as well, because while he is constantly encouraging Maggie and Maggie's independence, he can never seem to follow his own advice.