My normal writing process is very much fly-by-the-seat-of-my-pants with only a map of the underlying worldbuilding ideas to guide me.
So I find it disturbing, to say the least, to suddenly discover I've got 3-4000 words of detailed plot notes about the next-but-one novel on my to-do list.
(Working title: "The Stainless Steel Rat Gets Isekai'd." You're welcome!)