I find I have a tendency to overthink things when I design. Sometimes it helps refine a design - things like working out exactly which type of increase or decrease gives the best result. And sometimes it just delays things while I think up more and more options to investigate.
I have just had a lesson in spontaneity by starting on a new shawl. I spent a while trialling all sorts of things that weren't right, and then gave in and charted up something simpler that turned out to be pretty much exactly what I was going for anyway. (Some of the other options would have worked too, but it would have taken a lot longer to finalise it.)
And my next lesson in not overthinking will be putting together a couple of shawl patterns for a submission. That is, I'd like to do two, but I definitely plan to get one done - the second one will take a bit more messing around and may not come to fruition by the deadline. (I hope I can do it, I love the concept.) The first design is basically drawn up, just need to work out a few details and swatch. I'm actually a little surprised at how quickly it has come together!