Sims 3 - How...appropriate

I find it kind of funny how when Sims have group conversations and that third wheel Sim doesn't exactly match the facial expressions as the others.

For example, while on a date with a fairy sim (you can't see her wings in this picture), My Sim's brother (on the far left) decided to butt into the conversation to announce that a family member (who romanced this fairy before) is married. (Or in this case "Tell about So-n-So's other Romances".) Which in turn, caused her to freak out in cry, and my sim....just stood there and smiled...quite evilly - must be the shifty eyes he got from his mother.

I found it quite hilarious.