That was a great article that made my think about the way I evaluate people on their looks even though I don't like to think that I do and even though I make a conscious effort to do otherwise.
I look at that picture of the two of you, and intellectually I can say I know nothing about either one of you or your personalities. But if, for example, I were seated next to you on a plane, I'd be more likely to initiate a conversation with you (I'm not talking about a flirtatious encounter here, just a normal platonic conversation to make the flight less boring). In that picture, you seem fun and approachable, whereas your sister looks too stuck up to want to talk to me. (Or course, that evaluation says more about me than about either one of you.) And that premature judgment of mine is not being fair to either one of you. For all I know, she may welcome small talk while you might not. I'm also not being fair to myself if I let my judgment based on someone's looks keep me from getting to know that person.
And in your closing, you give great advice. When I've made an effort and introduced myself to strangers, I've seldom been disappointed, regardless of what they look like or what demographic category they fit in.