I love the building of a story and not just the initial pouring of ideas onto paper. That's all good and great, but anyone can get a brainstormed idea and write it on paper. The real mastery and love of a writer's work comes after.
The ability to look at the initial draft and instead of seeing a great story...can only spot the flaws and bad bits. Then, in true writer's fashion takes the story and molds it like clay: moving, tweaking, and reshaping until the flaws sparkle and the bad bits are gone.
Even then, it's not enough. They look at the revised work and see the implausible and unforeseen gaps in these character's story. At this point, only the most dedicated of writers will roll up their already wrinkled sleeves, wipe their brow of sweat, and dive back in.
They'll remove whole sections of unbelievability (even if some is of the most loved word usage) , delve further into the intricate of needed research to get the details just right, and turn that shiny diamond into a burning sun of perfection.
They'll know the manuscript is complete and that a part of them is in the story so completely they'll never get it back, even if it never gets published or seen by anyone but them and their beta readers.
Good writing all!