I can certainly agree with this. My very first attempt at a novel was just “start and write”. I won;'t even tell you how much time was spent later tangling with character actions that conflicted with the beginning of the story, or dead-end rabbit holes that had to now be unwound, or manipulated to fit with 20,000 words of prior material. 
My then wife was a practicing Psychologist. Way down in the middle of writing the novel, I’m picking her brain, and discussing at length…sometimes spread over weeks…the motivations of the main character. That was truly the wrong place to be hashing out how my character was going to act. I still love the finished story to this day, but I would never write like that again. I want to have a fairly complete understanding of my character, before I touch fingers to keyboard. That doesn’t guarantee that all obstacles or dead-ends will disappear. They’ll. just be much easier to navigate with some pre-planning and analysis.
Over the weekend, I started a new story. That’s not totally true. I’ve had the “itch” for a broad, sweeping political/mystery/murder story for about a month. I couldn’t even express it in more than a single sentence in a Scrivener file that I call “Future Story Ideas”…an “incubator” file with index cards and 1-2 sentence synopsis that very, very broadly outline a potential idea. Some become something. Some just get old, and eventually die…or my writing interests change.
There are a dozen major entities (companies, individuals, countries, governments) that have a potential place in this story that finally jelled. And, there are at least that many overarching plot lines that might be developed to tell this story. But, in each plot line, the major players could be reacting much differently…supporting a particular view in this storyline, but being against that viewpoint in another storyline. Today, I’m zeroing in on the particular winning storyline…the one that is most interesting and which offers the most intrigue.
However, in order to keep one of the other storylines from creeping into a character’s viewpoint, I set up a quick spreadsheet with each character, and a paragraph that describes how that character is to react in the selected plot. In subsequent cells, there are some snippets either to think about, or remember, as I write…some of the detail stuff.
And, for bonus points, I’ve linked the Google sheets to my Scrivener document. :mrgreen:
In another day or two, I should be ready to broadly outline the full thread of events from start to finish. The Corkboard and Outliner are excellent for this process, allowing me to drag broad sections around, and order them for the best reader experience. Then, as Jacob Hero pointed out, the characters can be set free to be themselves, in the moment as the actual chapter and/or scene writing begins.
The point of this “birthing” experience, is that I don’t diminish the excitement or importance of “getting to the writing”. However, a few days of contemplating and mentally playing with storylines certainly helps me. I’m no expert, and that’s why I need a roadmap to follow. However, I certainly do seem to write more calmly, knowing where my story and characters are going.
HTH
