So I told myself I had no interest in being a short story writer, that I was going to write and sell novels, and I believed me. When I did start writing short fiction, it was with purely mercenary intent: at the time, novelists had more luck with short story sales to back them up. Then I found out - horror of horrors! - I really enjoyed it.
More than that: I've been working pretty steadily on my novel projects of later, but took a break to work on a so-called flash piece. (I say "so-called" because the first draft clocks in at 1,333 words.) The satisfaction of setting up the opening, keeping a tautly wound plot, and then - most of all - finishing the story was glorious. I've also been mulling on a couple poems - which, for me, entails looking at forms I want to play with - and brewing on a fairytale reworking.
I've come to the conclusion I need the break and the change in pace, taking a step aside from the marathon of a novel to write something more contained. ... relatively, because I am a big fan of the, "Yes, but ..." ending, where the current tale is wrapped up, but the story implies there's more to come.