Raj: Uh, listen, I got a text from that girl Abby, and she and her friend Martha want to hang out with us again. What do you say?
Sheldon: I don't say anything. I merely offer you a facial expression that suggests you've gone insane.
Raj: I don't get it. You had a great time.
Sheldon: Yes, exactly, I had a great time. That's done. I've moved on to other things. For example, after I learn Finnish, I'm not going to learn Finnish again.