What not to say 101

"You are so skinny, why do you have double chin??"

(doesn't matter if u stated "skinny" first, she will still get pissed off at u. And I guarantee, even if you use "beautiful" instead of "skinny", u are still in the trouble of the century)

i.e. Lesson learned: think before you speak.......... to a girl, or a sensitive guy. Haha.