The other reason is that I've realized that I prefer to have a big picture vision of what I want to do, the techniques I want to use, a general idea of what will go where...but then I just like to let the finished product become what it will in the process of creating it. And not try to have too much control over it. It's true that I oftentimes don't, at first, like what I've produced, but I think there's something else at work in that regard -- like thinking that what I do is never good enough.
But if I plan something out in too much detail, then there isn't a lot of room for serendipity. And I often like to change things as I go. This happens for me with weaving much of the time. I'll have one thing in mind when I'm designing the piece, then other things will come into play while I'm in the process, and I'll end up doing something else. I keep reminding myself that there are no mistakes! What finally gets created must have been what was supposed to happen, or it wouldn't have.
At any rate, I AM thinking about things to come even though I'm only working mentally at the moment. Taking that summer vacation, now, that I never even imagined I'd have this year!