There came a transition somewhere along the line of my photographic evolution wherein now more often than not my favorite photos are the ones I see first in my mind and then go capture. That's not to say that I don't have favorites that I just came upon in the moment, just that the ratio has shifted.
My photographic evolution defined by where my favorite photos came from:
Phase 1 evolution - happenstance...
Phase 2 evolution - 50/50 happenstance/pre-visualized
Phase 3 [Current] evolution - 85/15 pre-visualized/happenstance
Looking back, I went through this with film but with less notice... but am now going through it in digital with more self recognition of it occurring.
I have reached a point where even on the fly I tend to find myself seeing the capture I want before capturing it... I find myself moving into position and adjusting camera settings to get 'that' capture - not thinking about it as much as just doing it. Though the more I think about doing that (doing instead of thinking) the clumsier I get - so I have had to learn to 'get out of my head', just focus on the image I have in my mind's eye and let my instincts drive the technical bits.
As an example, below are some of shots that I knew I wanted and talked my son into 'hand modeling' for me.
We were camping and kept walking past the little water spigot stations and I got in my head an image of the water diverted by hand and creating a spray of droplets - and, using depth of field, I 'saw' capturing the movement of the spray/droplets.
I was admittedly a little obsessed with capturing the image once I envisioned it - and my son, encouraged by my wife (I think mostly to shut me up), finally relented and came along for the 'shoot'.
Here are two of the shots I captured at the location I had envisioned these shots at as I wanted that silky smooth green bokeh in the background which I got because of a swampy area behind the spigot - the entire series producing 17 I really like ... and below those two is one I captured at a different spigot with a different background scenario...