For me it's the oppressive darkness. I like to know where im walking, and not have to worry about where my brightbloom seed is or whether a baby frox can eat it. Once I find a lightroot it's fine that I can see everything, but up until that point where a lynel or a silver moblin can be around the corner and you can't see it, and you can't see how to run away, I'm too scared towalk around.
Hence my fancycle + brightbloom is my favorite tool to get around.