I don't think being quick to forgive/forget is necessarily naive. On the contrary, in biology, it is part of a very successful strategy for social animals ..
I think I would bore everyone if I start to explain why, but should you be interested, you can read about
tit for tat and
prisoner's dilemma on wikipedia. Game theory is used by biologists to explain evolution of certain behaviours, for example in relation to animals that live in cooperative societies.
Other than that, it seems to me that you base most of your moral decisions on a sort of "gut feeling", but that you consider yourself nice by nature. Is that a good description?