When the story you're working on flips on its head. For me, it always happens at some random time during the day, when I'm not even thinking about my screenplay. Something someone says, or something I see, makes me think about my story and the whole world stops in its tracks.
The screenplay I'm working on had, until last night, been a romance. Our romantic interest was the A-story and our best friend was the B-story. Those roles just switched. It's now a "bro-mance", and our romantic interest is the B-story. This makes sense for so many reasons that I can't believe it took me so long to figure it out. Holy shit, it has so many implications in the screenplay, haha! Ripple-effect!
This post almost belongs in the lounge, because really I just wanted to share a little moment of joy. But no, this is for screenwriters. I hope some will share their Oh Shit breakthroughs.
Happy writing, y'all!