Everyone has a point of view, and situations and characters will look completely different from alternate perspectives. It's something you have to keep in mind when you're writing a book, or when you are reading one. For example, I remember when Harry Potter and the Order of the Phoenix came out, some people were up in arms because Ginny "suddenly" had a personality. They thought it was out of character that she was acting differently around Harry, or talking to him. The thing is, though, that the Harry Potter series is told primarily through Harry's eyes, and for the first four years he knew Ginny, she acted like a girl with a dreadful crush around him. It was Harry's perspective we were seeing. Had we been seeing the whole series from someone else's point of view, chances are, Ginny would have been seen quite differently.
Let's go to Exhibits 1 through 4 for reference. The characters being blatantly mocked here may possibly be extreme exaggerations of some of my current characters. >_> (They're getting their comeuppance for everything they've put me through in writing them over the last year. They'll likely get revenge on me later for slandering their characters by doing something crazy. Well, crazier than usual.)
Here in Exhibit 1, we have what's really happening. If this story were being told from a completely objective narrative and we could see into all three characters' thoughts, it would look like this:
However, what if this story is told from Character A's point of view? Only he is going to know the truth of what he's thinking. Everything else is based completely on what he thinks is happening.
Same thing for Character B. Everything's a little more extreme from her point of view.
Character C's thoughts on the situation will be exaggerated because of her biases and her perceptions of the other characters.
Character perspective is very important. Whatever perspective you use is going to be the way the reader is introduced to the world. You might make people hate a character in one book, but when you switch viewpoints in another book, the readers see a different perspective and they come to love the character instead. Someone might seem mean and bristly to one character but loving to another. There is so much impact on the story and the world because of how one character sees everything.
How do you want your characters to be seen? What are you trying to say about them? What are you hoping readers come to understand from whatever point of view you use?