Wrong number
Whenever someone calls me and it turns out to be the wrong number,
they never reveal this to me by asking for someone other than me.
My wrong number peeps reveal they are calling the wrong number by revealing what appears to be a secret.
Most of my wrong number conversations go something like this:

Me: Hello?
Wrong number person: I did it...
Me: Hmmmm.
Wrong number person: Hmmmmm?!
Me: Yeah.
Wrong number person: Who is this?!
Me: Who's this?
Wrong number person: I think I have the wrong number.
Me: I think you have the wrong number too.