This is a word of advice mostly to myself but also to other writers who happen to have favorite punctuation marks.
I am a huge fan of ellipses (AKA those three little dots) when writing, probably because I tend to write the way I think, and my brain is full of unsure, unfinished thoughts. But when reading, they kind of… get on my nerves, especially when I’m reading back through old stories I wrote and it’s like… every other… sentence… has ellipses… in it… not only does it slow the pace of the writing, but it’s also visually distracting.
Em-dashes are enjoyable for the same reason. An em-dash is a long dash often erroneously represented as two hyphens side by side or by an en-dash (which is a whole ‘nother post), but it’s really supposed to be a single dash the width of a capital letter M, hence the name. In word processing programs, they look like this —, but they are a pain in the neck to copy and paste from Word, so I take the easy way out and use the two hyphens most of the time.
In short, em-dashes can be just as annoying as ellipses—and just as much of an eyesore. Where ellipses can describe the dialogue of a hesitant or slow-thinking character, em-dashes convey the dialogue of a character who cannot finish a sentence without interrupting himself and moving straight to the next thought. It can give you whiplash when all of a sudden someone’s talking about books—but wait a second, did I tell you about the awesome restaurant I ate at last night?—oh, yes, I was talking about books, wasn’t I?
I try not to waste my time worrying about punctuation during first drafts because it always jumps out at me when I read them back over during revision or editing. In a world of plot holes and character inconsistencies, punctuation problems don’t look all that huge in the big picture.