I absolutely hate those emails that say "Sent from my iPhone". I usually reply back "Sent from my iToilet"
It's the default signature for iOS Mail. It tacks it at the bottom of every email. Guess people are too lazy/don't know how to change it.
I sign my professional emails with "respectfully yours," followed by my name and title.
I changed mine to "Sent from a mobile device". I want people to realize I'm sending short message because I'm on a phone, but I don't want them to get any preconceived notions about me because of the device that I use.