Oh, I keep getting that argument and I disagree completely. Swearing does not add nor substract emphasis; it is punctuation, placeholder words that might as well be onomatopeias. For an example of a character who swears constantly and still manages to highlight quite well differences in emotional intensity, I would suggest you look at Malcolm Tucker from british political satire The Thick Of It. For another who never swears yet also conveys utter fury, anger, frustration, pain, and so on impeccably, I would suggest having a look at any of the latest Doctors from Doctor Who. An angry David Tennant is a frightening frightening sight to behold. In the case of the hammer on your toe, I believe a heartfelt ARGH! does the trick nicely, with an extra hiss afterwards is you feel like it.

I keep trying to tell my mom exactly this, every time we need to design some kind of print materials for the family business. She just doesn't get that emphasis is about the relative share of a reader's attention to different parts within a text, a positional good of sorts.