... is when people block-quote the entirety of a previous post despite that text not really being necessary at all for comprehension.  That's a big ol' chunk of text that just takes up space and makes it harder to navigate the thread, without serving any real function.  Unless one actually needs to respond to a specific part of a previous message, or the post would be hard to follow otherwise, just the plain old "Post Reply" link should suffice.

Just thought I'd mention it.

Edit: Ambiguous topic titles would be another.  Anybody got any others (apart from fussy admins )?

Trolls. But we almost never get them.

Spambots have to be the worst imo.

its a good thing you dont allow signatures on here. On pullipstyle we had to enforce limits because some people had nearly full-screen signature PICS, and they would show in every single reply,, ugh...

My pet peeve are parrot posters.  Those who take a point that's already been stressed by somebody else, and either re-words it slightly, or blatantly states the same exact thing -- with zero acknowledgment to the original poster.  (It's especially irksome if that point was made in the very first post, so it's not like you may have accidentally missed it in the middle of a thread.)  A "like he said," or "It's as she mentioned" goes a long way to offering due credence to a contributing post.

My biggest pet peeve is also something that doesn't apply to this place - any time someone quotes MASSIVE IMAGES.  That's way, way worse than people who quote giant blocks of text.

Okay no, my BIGGEST pet peeve (that does occasionally happen here) is when people decide to be jerks to other people just because they know they're anonymous on the internet.  In general, though, people who post at STC are pretty civil, for which I'm very grateful.

My pet peeve is parrot posters who take a point that's already been made by someone else and either repeat it with minor rewording or state the same thing verbatim with no acknowledgment to the OP.  (It's particularly irritating if that point was made at the top of the thread, where it couldn't have been missed.)  An expression of concurrence with the poster who made the point first would go a long way in giving due credit, e.g., "as Adam astutely noted, . . . ."

Political shouting matches, mostly. Nothing good ever comes of them.

Oh, and animated emoticons.

Aside from those, I can take most things in stride.

I briefly considered posting a similar comment but thought better of it

As did I. Gotta be one of the better ways of trolling Angie, other than saying Twin Snakes was better than the original.

But it is... 

I like your new look QGJ!

I hate that too, especially when they are stupid, ugly, memes (or at least of similar points).

Then of course there's chat speak that makes me wonder how a person can even be smart enough to play a game.

Squawkers, the lot of ya. 

Luckily, I've brought crackers for everyone.

in forums where you can post pics, replying with an inserted picture 1 pixel high by 30,000 pixels long (i think that's photoshop's max) will stretch out everyone's responses onto one line.

Hmm I was kind of curious what pet peeves people had on THESE forums, but I guess everyone's happy here.  Or else you're all just really polite.

I am very happy--as people's pet peeves about other places attests, most of the typical forum pitfalls are a non-issue here. But with "you're all just really polite" in mind, my pet peeve is responses to posts that appear to be solely designed to insult or offend another poster, particularly when such responses make up the majority of a member's posts. We're all a pretty mature and respectful group, but every once in a while, snark rears its ugly head.