For me, bad grammar, typically amongst the younger groups, but with grown adults it's even worse again. Using "ii" for "y" and text/street speak is so completely and utterly cringing that I literally scream at them in my head. I feel like beating them with a dictionary in a hope that the words might magically make their way into their brain. It's the easiest language to learn and you learn it from the minute you learn to talk. So it's not hard. I dunno why I'm ranting about this, but fuck it. I have to get it off my chest cos it really, really, really, really, really angers me that people can be so blatantly ignorant and lazy. When I type to someone, I want them to be able to understand everything I say. Not spending 3 times as long trying to work out what I've just said. It's so bad now, it's really embarrassing and an insult to our language. IMO.