I though I would start a grammar pet peeve thread. Feel free to add your favourite posting and writing peeves. I am by no means a grammar expert and my spelling is getting atrocious the older I get. But I notice more and more that the quality of writing in newspapers and blogs is really dropping.
My first and most noticed complaint is that most people posting in the various forums I visit, is the no one seems to differentiate between 'to' and 'too'. I know it seems trivial but in reality they're 'two' very different meaning.
I agree with sharpnfuzzy; that one drives me up a wall.
Before I started using Firefox, one word I always spelled wrong was definitely. It took a while to train myself not to type definately, but Firefox's built-in spell checker has slowly managed to change my ways.
The one I always laugh at is when someone tries to correct another person's grammer.
On a final note, one thing that I can never get used to (even though it's technically correct) is the phrase in-built. I've always said something is built-in and thus, I always thought it was the right way to refer to it.