On length of tale

I realized something fully last night that has been in my mind for about four years now.
I admitted to my parents that I think in novels, and I can very rarely fit all my ideas into a short story.  We got on this topic when we started talking about my January Term (henceforth referred to as J-Term) course, The Playwright's Process.  The final is not a normal final: it's a fully written, developed, and edited one-act.  For those of you who aren't fully familiar with the world of theatre, one-acts are generally the short stories or novellas of the stage (you can, theoretically, resolve a larger plot line in a one-act, but I've never seen it done; after a point, you need more acts).  One-acts are generally between 20 - 45 minutes long (again, you could see longer one-acts, but I haven't); according to Wikipedia, a new sub-genre has started called "flash dramas" - one-acts that are only around 10 minutes long.

Anyway, this J-Term course is going to be a challenge for me.  As I previously stated, I think in novels - stories that take two or three acts to resolve.  To scale down one's thinking is something you rarely hear - most motivators I've heard tell their listeners to think big and shoot for the moon.

But maybe scaling down my thinking is not what I need to do.  Maybe I just need to think differently.  Not scaled-down, exactly, but just not as big a scale.  Maybe I should think big, but not as big as I'm used to thinking. Maybe, over the course of this J-term, I will realize that I'm actually more of a short-story writer than a novel-writer, and I've been fooling myself this whole time.  I admit, I need to put my characters through a fat lot of crap before they make it to the end when I'm writing a novel, but I always have trouble coming up with more than a little bit of crap to throw in their faces.  Maybe that's the main difference: the crap that gets thrown at people is a different sort of crap than the crap in novels (smaller, perhaps, but no less disgusting), and the hands that throw it are smaller than the ones that throw crap in longer works.

So, dear readers, what do you think?  Any one-act/ novella/ short-story writers out there who would like to share some opinions on the writing process?  Anyone who's done both and would like to offer sage advice to a college student?  Feel free to comment!