I'll start the ball rolling - commas - I usually have too many, or not enough. Or worse - the right ammount in the wrong places!
...and let's not get started with any serial comma back-and-forth. I struggle most with commas and semicolons, though my understanding of each has vastly improved since the early days. Still, I'm not immune to the occasional splice. If I'm unsure about a semicolon, I will sometimes rewrite the whole sentence so as to avoid using one at all.
Semi-colon. Commas I'm ok with, and for a while I used to make the mistake of putting a capital letter at the beginning of a word following a colon, but now it's just the semi-colon that I struggle with. My doubt over it's usage means tend to resort to a comma because it feels safer.
I don't really have trouble with any punctuation marks. I do have to say, however, that I hate parentheses, at least in fiction and poetry. Parentheses almost always mean the writer hasn't thought his prose through well enough, and he forgot something important. A famous example, from Edward Bulwer-Lytton's Paul Clifford: It was a dark and stormy night; the rain fell in torrents — except at occasional intervals, when it was checked by a violent gust of wind which swept up the streets (for it is in London that our scene lies), rattling along the housetops, and fiercely agitating the scanty flame of the lamps that struggled against the darkness. You can almost hear Bulwer-Lytton saying to himself, "Oh, yeah - I forgot to mention that this is London! I'll just stick it right here, in parentheses."
Have you had the joy (har-har) of reading Something Happened by Joseph Heller? It is riddled with endless parentheticals.
Yeah, that example does seem pretty sloppy, you can almost hear him saying "whoops!". Maybe he was using a typewriter. I think if you're writing from a first person perspective then it is more acceptable to use parentheses, if you want it to feel like the narrator is talking naturally - who you may not want to be immune to mistakes.
The interrobang is my nemesis. I'm never sure when I'm ready to commit to one. Such a tricky beast...
Yes. I forgot about that one! How do you use it?! EDIT: I've got it. Have your characters ask questions quietly.
I also get unreasonably upset over incorrect ellipsis usage. Some people use them correctly... others seem the think they need more periods..... or less..
Naw dude, I totally feel you there. The ellipsis is one of my favorite punctuations. It is beautiful and should be respected. That trail into nothingness... It can speak volumes.
I fear I struggle most with understanding the em and en dashes and hyphens. I know there is a difference, but I have trouble grasping that difference. The internet gives me mixed answers. I also have this question, What are the spacing rules for using the dashes? I use them sparingly enough, but I feel they are appropriate at times and want to use them correctly as oppose to avoid them. The ellipsis poses some questions as well. In short, should it be done as "this blah blah blah..." or "This blah blah blah. . ." I really only use them if I'm taking an excerpt from the middle of a quote or if I have a character trailing off. If I used it in this sentence, how would it look? "But what if... No, that will never work."
Semi colons! I try to avoid using them for fear of using them incorrectly. I need to brush up on them because it's something I really want to master. YES! This is one of my biggest pet peeves in fiction! I cannot stand it when people do that. It does look really sloppy. I enjoy them too. I think a lot of people use them too often and incorrectly. They do speak volumes and less is more, imo.