"You're very pretty"

My sis and her bf went for potrait (more like caricacture) drawing at genting.
She was very excited when she came back and showed me the drawings (which is pretty good ..looks alot like my sister's face)
however, it's not the drawing that she's excited about.
It was what the artist said to her, I later found out.

Sis : ah jie, you know, before we leave, the artist told me that "you're very pretty"

well, she was elated and very happy until her bad sister (that's me lah, who else? ) poured cold water

me : how you know that he (the artist) is not telling every customer that?
sis : yer...where got ah jie like that one? you let people happy for a while cannot wan meh?
me : ok la .. he didn't tell every one, just tell a few only include you =P