I think that most girls like to have some control.. And when girls argue or make arguments, (especially me) they like to kind of believe that they have a point to make - and they like to be fought against, so that they can stand their ground and convince you that things aren't right or whatever.
Its far better to have an argument where two of you believe two different things but then come together with some kind of agreement. Although its nice sometimes for a boy to say you're right, of course. Most of the time, its nice for the girl to have to 'win' the boy over, or even not 'win' the argument at all.
Its not a bad thing to be too nice.. it just means you are caring and comforting and understanding.. But girls enjoy mystery and having to work lads out. When everything is laid out on a plate, things become too perfect, and there is nothing left to work on or correct.
Don't change. Just try to respect that imperfections are normal and okay.