Answer:
As soft as silk, as white as milk, as bitter as gall, a thick green wall, and a green coat covers me all.
At night I come without being fetched. By day I am lost without being stolen.
I can ruin your day, or darken your life. And while I'm expected, I'm never alright. I'm bad for business, and worse for your hair. Wherever I am, there's something not there.
You can spin, wheel and twist. But this thing can turn without moving.
What turns everything around but does not move?
This food is a tortilla filled with cheese and sometimes chicken before being heated or cooked.