I find passive aggressiveness to sometimes be a sign of covert narcissism--an under the radar way to regulate self-esteem by devaluing others. I'd take the overt one any day. At least you know where you stand with them and can adjust your defenses accordingly (fun fact: if you want an overt narcissist to leave you alone, cut off their emotional vampirism by being reaction-less or ignoring them completely. No one will go to a restaurant where there was nothing to eat). Sometimes it's cultural, with some societies disallowing expression of anger for example. Other times it's due to family of origin issues, when kids were punished for speaking up. Also, this is the Age of Social Anxiety, and many have a hard time coping with conflict, collecting avoidance strategies as if they were positive, healthy alternatives to experiencing authentic contact, emotional intimacy, with another human. Eye rolling, shaking of the head sadly and lip puckering are some of one's I hate the most.