I have issues with poor punctuation and grammar, especially on signage. Most of the time I can grit my teeth against it and carry on. Incorrect use of quotation marks, however, is something that drives me over the edge.
Neil Gaiman posted a link to The “Blog” of “Unnecessary” Quotation Marks and made my day.
And just because, I’m including an Angry Flower comic that Lightspeedchick modified for me a few years ago. Bob’s Quick Guide to the Apostrophe is the original (which is also very funny because it is true); her modification for me is below.

This made me laugh, but not as much as the icon you used! LOL!!
HRH
Did you immediately envision Blade turning to you and saying, “Quick, to the Bat-Cave?” :P
You must, you know, like, spit everytime you read my LJ. I’m so, so sorry. I had better break out my Fowler’s. Of course, if my grammar wasn’t faulty I wouldn’t have need for an editor, right? Then I wouldn’t be able to hire you…
I do not spit! (Ever. But especially not when I read your LJ.)
There is a world of difference between casual personal journals, and so-called professional commercial signage. And you’re not as bad as you think you are. Everyone forgets a letter here and there, or their fingers type a homonym. These are not hanging offences.
Have you read Lynne Truss’ delightful “Eats, Shoots & Leaves”?
that’s hilarious
Do you know about Grammar Girl?
http://grammar.quickanddirtytips.com/
I subscribe to the podcast and it’s delightful. I think you’d enjoy it.
I do know about it; in fact, I have a link on my sidebar to it! I’m not a fan of podcasts — I can read quicker than people can deliver their info aloud, plus there’s no download time — but I read the transcripts. It’s great fun.
Podcasts: I know what you mean. I ahve a short attneiton span with the computer so I often find I need a break from reading online and poscasts are a nice alternative. I often listen to them instead of the radio in the morning or while cooking/cleaning/driving/commuting/exercising, etc (Especially since I find Montreal radio is horrendous!)
Gah. Sorry about the typos in that last one.