Poor grammar is a pet peeve of mine. Fair enough I make a few mistakes, like many people do; but I also think there is a limit to how poor grammar can reasonably be.
Most of the time I find people who don't use punctuation to be intolerable, but special acknowledgement goes to the following...
- Needless abbreviations, e.g. 2 instead of two (I'm sorry, saving yourself the time and energy of missing out two letters is not remotely justifiable).
- Getting you're and your confused* (this is also interchangeable for they're, there and their, but not to such an extent).
- PEOPLE WHO USE CAPITAL LETTERS TO EXPRESS THEIR POINT.
- A lack of spell checking. Everyone can misspell words, it happens to all people, from professional authors to shelf stackers. But some people just refuse to correct their spelling before they post and that annoys me.
- Confusing bought and brought with each other (Ok, I do this from time to time. But some people do it all the time and that annoys me)
However, even though it annoys me I like to think I refrain from picking on people's grammar. I rarely attack someone based on their grammar.
(*I'm talking about the incorrect contractions of words, such as using "your" to mean "you are", which should be "you're")
...
With all that said and done, I would like to note that I myself have poor grammar, I accept that, so I also accept that I am a bit of a hypocrite.