Introvert sims could enjoy social interactions, talk less and listen more, need to be introduced before talking to somebody new. They could be good listener (secrets). They should enjoy solo activities more and group activities should be exhausting (Draining Energy more than usual).
Extrovert sims could talk more, look for social interactions with anybody nearby, never visit a venue alone. They could be good at sharing informations about themselves and others (traits, sexual orientation,secret). They should enjoy group activities more and solo activities should be boring.