Okay, so this isn't really a big deal, but as I have mentioned in previous posts, my girlfriend's daughter (age 16) never seems to address me when she comes or leaves. It's always "hello, mom", or "bye, mom", as if I don't exist. She is never blatantly rude to me, but I find it disrespectful.

I have nothing to do with the father of the children as it isn't my job to parent them. He himself is rude, passive-aggressive, and petty and doesn't acknowledge my existence either whenever he and my SO talk on the phone. Never does he mention my name, and when he tells my SO that the kids are coming over, he'll say, "to YOUR place".
Furthermore, the biological family irritate the HELL out of me. They are all very centered on the children and will drop everything whenever they come into town and spoil them. Every time my partner's daughter goes to her grandparent's place, she gets a new pair of shoes, clothing, or something else. This past summer, the relatives went all out on SO's daughter's Sweet 16, with a layered birthday cake, a hotel room, a big beach ball where everyone signed their names, and dad's sister even went so far as to request pictures being taken for a scrapbook and a DVD...Maybe I'm a bit envious as my relatives NEVER would have done anything like that for me when I was her age.

Anyway, I'm sorry for getting off track here, but I've mentioned the greeting issue to SO and she seems apologetic for it. I'm at the point now where I feel I'm grasping straws, so I am making a point not to bring it up anymore. I don't even make a point of greeting her if she doesn't greet me.

Another issue I've noticed is that SO's daughter always seems peeved whenever there is a birthday in the family and I buy a card for that person. For example, we were all out celebrating her older brother's birthday three weeks ago, and when I handed him the birthday card that I got for him and he read it (silently), I looked across the table at her and she was looking down at the card with a "pouty" expression on her face. It isn't blatant, but I do notice it, and it has happened more than once. I don't bother mentioning this to SO. I do question at times whether I am reading too much into things, but I see what I see.