Question

I hate bold text while coding. Is it possible to disable bold text (and underline) in every single file and emacs’s interface?

Answer 1

The easiest way is probably

(set-face-bold-p 'bold nil)

Another possibility, which also deals with underlines, would be to evaluate the following snippet in a running Emacs session:

 (mapc
  (lambda (face)
    (set-face-attribute face nil :weight 'normal :underline nil))
  (face-list))