"by the way, what r u goin to b on holloween [sic]?"
"The most original costume of all: myself. And you?"
"i was thinkin of goin goth-- i wanna see what i look like in guyliner!"
Me, for the next 10 minutes: clutching my sides, hysterically laughing. People crack me up. I just... it's not something you would've expected that person to say. At all. (Yes, yes, I'm one of those people who texts proper grammar.)
i always text with proper grammar too. it's my own little way of rebelling against the establishment, which in this case is standardized lazy texting.
i don't capitalize, though. there are some things that laziness always wins.
With the exception of capitalization and "OMG", I'm all about the proper grammar in texts and IMs.