Sheldon: Hey, isn't that Professor Proton?
Leonard: Oh, yeah.
Sheldon: Look at him just standing in line, like he wasn't moderately famous thirty years ago.
Sheldon: Let's go say hello.
Leonard: Oh, maybe we shouldn't bother him.
Sheldon: I'm not going to bother him. I'm going to talk to him.
Leonard: He thinks there's a difference.