|No, no, no--I said STRUCTURE, not A structure.|
The way people conceive of structure, too--that's different from writer to writer. Avoiding formula is, of course, a concern, but just coming up with a plot that actually WORKS is the primary concern for most of us, I think. We can finesse the fiddly bits later, once we've written the first draft and have something to fiddle with. (Advice I often dish out, but find much harder to follow myself.)
The truth is, there are so many possibilities out there for structures that work. So many variations on those structures. And so many different ways of writing about those different structures and characterizing them on paper, from Beat Sheets to outlines to (my personal favorite) flow charts. I think my default way of thinking about structure is Things Get Crazier and Crazier, and then The Big Crazy Happens, and then Character Resolves the Crazy. In other words, I'm pretty Aristotelian that way. Truthfully, though, I think it's because I can't keep anything more complicated in my head while I'm first-drafting. It's all I can do to just come up with scenes that more or less fit that structure, let alone get all fancy and break it down further. Perhaps it would be different if my sole occupation were writing novels, but sadly for my novels, my brain is crammed full of other crap constantly threatening to make the good stuff leak out of my ears.
How do you deal with it? Structure, I mean, not brain leakage? Inquiring minds want to know...