Remove default indent in plain text modes?

I've looked and I can't seem to find a way to force all text in plain text modes to default flush left. It always indents by my default tab stop. How do I fix that? And where should I have looked for the answer?

Always try in `emacs -Q` to see if this is something Emacs does by default or if it is something you configured Emacs to do (and maybe forgot you did that). In this case it is probably something you configured Emacs to do, since it doesn't seem to do that on my machine.

check if you have something like `(setq-default indent-line-function 'insert-tab)` in your config. i had this exact problem and that was the cause. maybe check the value of `indent-line-function` too.

That was it. I should have updated this to note it was solved.