she has never been mean to me
that is how I form my opinion of her
how she treats me
You NEVER form an opinion of a person based on how they treat you.
Even a sociopath can be nice to you if they want something from you.
You judge them based on how they treat low status people whom they can't benefit from.
This is why dating experts tell women to judge a guy based on how he treats the wait staff at a restaurant.