Luc: (talking about a cat, and crying a bit) ...I really miss her.
M: I can see you're really sad.

(a pause, whilst I look at his lovely concerned face)

Luc: it's hard for me to say this when you're looking at me like that...
M: (smiling) I don't know what to do about that!
Luc: ...sometimes I want to take the piss out of you. Like just then, I wanted to say "WOW, well done, how did you work that one out?" ...but that's so mean - you're so nice!
M: well, I disagree with both those statements...
Luc: oh, okay... I guess I will take the piss out of you then!

It's just really cute that he thinks he isn't nice. He's nice as f**k.