Both are. Both have their purpose.
Together they can create a powerful book.
You can summarize when you want to recap what you have just written. This can be quite helpful if you’ve introduced a lot of concepts, and you want to make sure that your readers understand the main points (nonfiction). When we summarize events in fiction, we surpass time (speeding time up) and skip over mundane parts that do not move the story forward. When we write in more detail, we become meditative and give the reader reason to ponder. We paint the picture and let the reader fall into the scene. We let the reader go in between the lines to imagine and create.
When we share stories, we share experiences with others. Stories filled with details, description, and emotion resonate with readers. Stories are like hooks that draw readers in and keep readers turning pages until it’s way past midnight. Stories are powerful tools, both in nonfiction are fiction, which create connections between readers and authors and readers and characters.
Showing is so much more powerful than telling. Ask yourself if you would like to be told how to do something or if you would like to be shown.
I learned how to bake (and cook) by watching others, by being in the kitchen with them, talking and laughing with them during the process, by feeling the consistency of the dough and tasting the raw batter. Recipes are summaries of how things should be made. They tell us what ingredients we need and what to do in what order; however, as we bake, we also experiment and explore, and we all put a little bit of ourselves in what we bake. We may add more chocolate or leave out the salt. We may use butter instead of margarine. Do we bake these cookies with love? Do we want others to enjoy them or are we giving them as gifts?
So, when writing, do reaffirm your message but ask yourself what will resonate with readers. Do they want to be told what to do and think? Or would they rather experience the alternatives through your characters, setting, dialogue, descriptions, metaphors, and symbols and feel as if they are discovering this on their own?