We've all learned this lesson at one point or another in our lives (probably more than once). It's pretty simple: sometimes you are willing to be a better friend to an individual than they are willing to be to you. What does that mean? I see it as an imbalance in give and take, i.e., one gives and the other takes (even if they just aren't that into you). :)
I learned this the hard way with a group of people all at once quite a while ago. It was not a fun experience and I swore that I wouldn't let it happen again. As a result, I have a few friends that I like, respect and trust and if I don't get a vibe of interest with new acquaintances, I don't let it bother me.
Of course, we all have our little groups we fit into. I remember, growing up, that everyone talked about cliques and the "in-crowd" or the "out-crowd". I'm sure I cared that I wasn't EVER part of the "in-crowd" at varying points, but I'm actually pretty happy to say that I avoided feeling much angst about it in the long-term.
It's not all that different in the "adult" world. Most of my friends know or have probably guessed that I lived a pretty sheltered, goody-two-shoes life in the Bible belt (and really, I don't think there's a thing in the world wrong with that - it's just a fact of my life). I also think that the ones I trust and respect don't let that affect the way they relate to me. But then I run into the odd person who seems to judge me for being too "wholesome".
What I can't figure out is why it's so hard to relate to me for having a different life path. I don't interview people I meet to find out whether they were/are a smoker, were/are into drugs, etc., and then decide not to associate with them because of their life choices. You are who you are and your experiences shape you and lack of experience doesn't automatically render a person naive and shallow (neither does a wealth of experiences automatically give a person depth).
I genuinely appreciate the different perspectives I get from the friends I have who have backgrounds that differ from mine - we all need a fresh perspective sometimes! I don't judge the choices/actions they've made; it's all part of life and every choice has an impact on who you ultimately turn out to be.
My Two Cents (and what I'll say to Brandon when he's older): Life is too short to waste time putting effort into one-sided relationships. Be thankful for and cultivate genuine friendships that will make you a stronger individual. Most of all, be a good friend to your friends.