Ed thought about experimental design all the way home. And the more he thought about it, the more he realized what a fucking nightmare the whole thing was, with confounds and biases absolutely everywhere. This wasn't a chemical reaction that he could isolate and observe, and then control. This was romance, and romance was a scientific disaster.

A Game for Two Players by lightgetsin (fma, roy/ed)

I have many favorite passages but this always sticks out in my mind because i love the expression "romance is a scientific disaster". So much that it became my tag for romance logging for a time, and my meta tumblr account.