QED

The phone rang at about 10:45 last night awakening me from about a half hour into my troubled Sunday night slumber. The missus is suffering from a cold at the moment so I did the decent thing and answered it.
'Hello mother-in-law' I said.
'Hello, how did you know it was me? Do you have call recognition on your home phone now?'
'No, you are the only idiot I know that rings in the middle of the night'.