An EX and I used to share a place and bills. He was responsible for paying the phone bill while I was responsible for paying the electric, cable, cleaning the house, doing the laundry, keeping a smile on my face, and driving everywhere...
After coming home late, he accosted me at the front door, ***Verizon*** Letterhead in hand and asked, "WHO were you calling in YONKERS?"
ME: "What are you talking about?"
HIM: "There's an hour long phone call from here to Yonkers, and it seems like it happened late at night..."
And so I inspected the phone bill myself... carefully calculating the date and time, relating it to my life and plans and simply said.
"Wasn't that the night you decided to call your OLD GIRLFRIEND to 'catch up' ???"
Apparently, where he thought I was having a mobile love affair, he was caught red-handed having an over-long conversation with a girl who was long-over him.
Have you ever accused your SO of something, only to find you're the one at fault?
***confirmed: service provider was VERIZON. see comments for details***