Let’s look a little beyond the obvious (anyone who’s abusive or unsafe).
Worry about those who talk a lot but never listen . . . those who won’t ask about your deepest hopes and dreams. They might make ok bosses or family members (from a distance); but you could waste a lot of time trying to force the wrong people to care.
Worry about those who act like they’ve got you pegged before they get to know you. Their relationship won’t really be with you, anyway, but with some image they’ve preemptively fostered in their mind. You won’t be able to really show or tell them much of anything.
Worry about those who won’t question the things they hear or think. Some seem to want to disappear completely into headlines, spouting back the sound bites and sums of talking points they know their side abides by. And when their side begins to justify atrocities, they’re the ones who’re made generals.
So worry about the inconsiderate, the judgmental, and the thoughtless. No matter how much you think you could mean to such people, the truth is they could convince themselves to turn and crush you in an instant.