I just now ran across a 1997 writing of Jonathan Shewchuk: Three Sins of Authors in Computer Science and Math. They are:
1. Grandmothering. That is, writing an introduction that does not tell what the paper is really about, often making it both inaccessible to newbies and obvious and irrelevant to experts.
2. A paragraph-long table of contents in the introduction. (e.g. "In section 2 we survey related work. In section 3 we go over some preliminaries...")
3. Essentially copy-pasting the introduction into the conclusions.
I've been guilty of at least the last two simply out of the oral tradition of CS folk. Oops. I did always think the Table of Contents thing, while logical for book introductions, was a little silly for an 8-page paper where you're already worried about space. As #3, I suspect it's to make sure reviewers do have a "takeaway" message, in case they're too lazy to go back and read your introduction. However, if you have to re-state all your major findings on the last page in order for people to figure out what you've done, then the rest of your paper must have been poorly-written.
I am rather ashamed at how my writing skills have slipped since I changed majors five years ago. I could probably still pass freshman comp (and I have it easier than many of my fellow grad students since I get to write in my native language), but it's nothing like I could in the heyday of my high school journalism career.