I’ve given much thought to the monsters you fight in RPGs or videogames, just hanging out until you enter the room, and then pouncing. What is it they do as they wait? Are they waiting? Or are you just catching them on the unawares? Are you bursting into their home and murdering them and their family? DM only knows.*
The ripped page is a total riff on the D&D pre-made scenarios, of which I have run quite a few. Over the time though, I’ve leaned away from leaning on these, feeling that they tend to inhibit more freeform storytelling. My current philosophy is to prepare some names for NPCs, some enemies, and some possible set pieces, then improvise based on what my players do. It avoids railroading and makes me feel like a more dynamic story is being told, and one that I don’t already know the ending to. That makes it all the more fun for me.
*I would like for people to start saying ‘DM only knows’ instead of ‘God only knows.’ I hope that catches on.