Awarded for a sense of humor ;)
Sometimes you get calls that are wrong numbers or dials from in someones pocket, but if you get one that sounds like someone in the shower singing Stevie Wonder "I just called to say i love you", you can get the Order of Smile achievement during this call.
After the initial Hello this is 911 options if you don't hang up and ask do they have an emergency again and they keep singing, it should then give options to sing Lionel Richies Hello.
is it me you're looking for?
I can see it in your eyes
I can see it in your smile
You're all I've ever wanted and my arms are open wide
Cause you know just what to say and you know just what to do
And I want to tell you so much, I love you
You hang up automatically and the achievement pops.
There may be other calls that will award this but it unlocked here for me.