What did it teach you that you didn't already know, Jeff?
Mostly that people don't ever like being treated differently based on any physical aspect of their appearance. I thought I was aware of this before, but I think that there are specific circumstances (like the one Zeronyne went through) that can be avoided with a little thought beforehand. I'm sure the flight attendant wasn't being malicious... she just wasn't thinking. A little more training would do her some good.
I think folks from the Midwest often have the most trouble with this, because so much of the population is of one race/religion/background in one area. Here in Los Angeles, we have the highest racial diversity in the nation, so from day one, you're used to seeing all kinds of different people mixed together in the same place.
None of it has made me walk on eggshells around anyone, though. I guess most of the stuff about treating people how I'd like to be treated has mostly been second nature to me, so I really never worry about it, and have never had a problem in this regard.