All that Glitters has an essay that totally speaks for why I am a B/Xer. Italics are mine.
And now, I sleep.
It's about the perservence of hope through all odds. It's about believing in something when you have no logical reason to, and yet you can't let go of it. In short, we are the Xanders of the real world.
Faith is all we have right now. We don't have kisses, hugs and cooings on a daily basis, and yet we still believe. We live in the mottled shadows and in the insignificant moments of interaction between Buffy and Xander. We relish the angst and keep coming back for more.
We have to want this relationship bad enough that we can see it playing in episodes already. Some of us can--those who write mountains of detailed fic--and we choose to share it with others. And yet others can as well, but their hope dwindles because our characters are portrayed as more and more distant with each passing show. We can't let this happen. There are few enough of us as it is, and the hardcore ones are even harder to find.
Part of my faith in this relationship is my knowledge that I've made it this far--until season six--preaching to my fellow watchers about how "BX will happen as sure as the sun will rise." Why would I make such a ludicrious statement if I didn't believe that it would? Giving up my passion so easily would be ensuring world-wide darkness the next day. If you've come this far now on the notion that love is as simple as buttering a piece of bread, then maybe you don't belong as a shipper of BX; try again elsewhere.
Remember hope makes us the people that we are in reality. It lets us choose what we want, what we want to obsess about and what 'ships we're passionate about. So, if you really don't want to give up the BX ship, then don't.
And now, I sleep.