Does anyone know what it means when you write sentences that contain phrases like "I had walked" instead of "I walked," adding various forms of "to have" between subjects and verbs? I believe I've seen I saw something about this before, but I can't remember what it means. I have a character that always writes in this fashion (based loosely on me), and I'd like to find out what this means so I can possibly develop this plot line.
EDIT: I don't care at all about the grammar, I'm looking specifically for the theory. It had something to do with low self-esteem.