What moves your book forward?
Sometimes I use small inconsequential things that no one realizes the ramifications of until it’s too late. The letter that was never mailed, the plane that left five minutes early. Things no one suspects will change their lives forever until they do.
Or sometimes I make it so huge that the characters know through every moment of it that the proverbial shit is about to hit the fan.
I actually like a mixture of both. Because like life, either one can change the final outcome forever.