My favorite is still this story, which I witnessed live in action...
(It was not on an iphone, but a T9 phone from a few years back... the T9 was some sort of text-intuiting system on a numeric keypad that would guess what you wanted to type. Sometimes it was great, other times, not so much.)
A friend of mine, up-and-coming in his career, received an email from a reporter asking him to send her something she needed for a story she was writing about him. He sent it from his phone, with the charming intro of "Here ya ho."
It was supposed to be "Here ya go." G-O, not H. Luckily, she has a great sense of humor, and we still laugh about it. I can only imagine her expression reading it the first time though...