You know, my dad has always been a little racist. Not in an aggressive, angry way, but he has some crass ideas on things and sometimes would say off-color remarks. Now, I know my dad, and he doesn't mean any harm, that said:
A few months into my relationship with my current (and final) GF, we went and visited my parents. I still had to commute to work, so she stayed behind and hung out in my old room while I was gone. Apparently, while I was away, she overheard my parents talking about her. My mom was commenting on how she had such a little "helium voice," and my dad replied with "Well, she is a little oriental girl."
Now to me, my mom is just being mom, and thinks my GF has a cute voice. As for my dad, I know he didn't mean anything by it, but that isn't the way my GF took it.
Alternatively, she comes from a very diverse (and very large) family. Not once has my color or ethnicity been a topic of conversation; only that I'm already like a son to her mom (after 3 years of being with her daughter). They've never made me feel like anything less than family.
That isn't to say my parents aren't nice and welcoming to my GF, because they are absolutely great. That also isn't to say that they don't love her, because they really do. After all is said and done, though, just that small remark has been enough to make her feel like she isn't really a part of my family... That's what happens when you describe/treat people in an "otherly" kind of way - it makes them feel like they are an outsider.
Small words, but people don't sometimes realise how much weight those words have, and then the damage is done.