I'm the type that plot literally everything about the story before writing it down. Sometimes, I'll even plot key dialogues. I have a file where I write down whatever happening in each chapter, from start to finish, sometimes even mentioning what the characters talk about. Though, it's mostly a detailed "what's happening in this scene, what's happening next". The actual dialogue, the detailed setting, and all that will flow naturally as I write them down. Sometimes, the details can be different from what I have planned, but it won't affect the story's plot in general.
The reason why I'm doing that is to be sure I don't get writer blocks along the way, especially if I've published my stories online. It also prevents me from discontinuing my story, and it is easier to maintain a scheduled update. For example, the novel I'm posting now is pre-written. It's already finished, though still not fully published.
On the other hand, the downside for me is that I'm too laid back to myself. Since the story I made is plotted from the start, I don't brainstorm too much along the way. It's like having a cheatsheet on your test. If I forgot what to do next, I can look at it and know what is next. And, with my story, for example, there's no deadline for myself since I have written down everything. So, yeah.
Though, since I posted in Tapas, I feel the urge to try "pantsing". Perhaps, I would love to do it at least once, just playing around the characters! I'm not gonna jump right into it with heavy setting, but maybe, a little slice of life can be my start on it.