Fahrenheit 451

According to Clarisse, Montag is different because he looks her in the eye when she talks to him.

"You're not like the others. I've seen a few; I know. When I talk, you look at me. When I said something about the moon, you looked at the moon, last night. The others would never do that. The others would walk off and leave me talking. Or threaten me. No one has time any more for anyone else. You're one of the few who put up with me. That's why I think it's so strange you're a fireman, it just doesn't seem right for you, somehow."