Amy: I'm not sleeping on the couch 'cause you don't know what's private and what's not.
Sheldon: This isn't fair. You've discussed aspects of our physical relationship with Penny.
Amy: That's different! She's a close friend, not the lady in the cafeteria who cuts the crust off your sandwiches!
Sheldon: That lady has a name. I don't know what it is, but one time, I accidentally called her "Mom".