If there is one thing i cannot stand is any variant of "Pardon my brevity. Sent from my iPhone." when i receive an email.
You may be wondering why. I'll gladly tell you! It's why i'm writing this post!
First, i perceive it as lazy. Control your device, control your software, control your freaking signature.
Second, it's just plain strange. Apple talks about how great their products are, how easy it is to type on, etc but this built-in message completely undermines that. It's saying to me "this message is short because i'm using an inadequate input method/device." I just don't get it - why say such a thing? I use Swype on my phone and it kicks ass for input, so don't tell me you can't write a reasonable message on a phone.
Third, it's an advertisement for Apple. Don't advertise at me when emailing. Seriously that's just rude. Great and self-serving for Apple, but this is YOUR phone now, don't be a cretin.
I realize there are probably plenty of people who don't really know that they are doing this when they send people a message from their phone. let this be a wake-up call!
And before you Android folks start feeling all smug, you may want to check the signature block in your mail client of choice. I have discovered similar things before in my phone.