Only a fool worries over what he can’t control.
I'm just very careful with my words when I write. Obsessively careful. I'm the sort of person who worries about the difference between "slim" and "slender."
Soft fantasy worlds have a much looser cause-and-effect relationship. Alchemists can turn lead into gold and nobody wonders about how it will impact the currency system. Someone waves a wand and turns an elephant into a mouse and nobody worries about conservation of mass.