I basically "know" what I am getting in a sense. Whether it will be any good is another story. In the past, any truly "good" photos were accidents; I always captured the image/subject I intended to, just usually not how I wanted it. I'm not good with light or composing, so most of what I take are "boring" snapshots; I get the subject I want, but I really don't know how to make it interesting.
I'm getting better, though.