...and I learned something new today

As it turns out, my pizza dough wasn't stretchy enough because I didn't knead it enough, not that I kneaded too much. Now that I think about it, I've never made a yeast-based bread on my own before, never had to think about how long to knead (until it can be stretched to translucency without tearing, it turns out; thank you Michael Ruhlman). Lesson learned!