This one is pretty easy:
If you want to know the people around you, watch how they treat people they don't like, especially those who aren't in much of a position to protect/defend themselves. The "low hanging fruit". Do your friends go out of their way to instigate and antagonize them? Do they take every opportunity, make every excuse, to spin everything said into some kind of *bad* thing they must constantly combat? Are they kissy-huggy and cutesy towards you, but toxic towards the people they don't personally like?
More importantly, are they narcissistic enough that they can't just dislike a person they have little in common with, everybody they don't like must be some wretched villain of some sort?
Then the people around you are showing you, and EVERYONE ELSE, who they really are. Not when they're being take to your face, but when they drop the façade and show their ugly personalities to the people they dislike. Especially if someone doesn't need to be saying anything TO or ABOUT your friends in order to find themselves being targeted with more snark and/or hostility.
......but I get it; nobody's trying to hear that. Nobody wants to run a critical eye over the company they keep and make difficult and uncomfortable realizations. Better to walk through life half-asleep with their minds and ears closed, flapping their lips on subjects they know little or nothing about, having to do with strangers they've never tried to know, and have no intention of trying to know.
And I know this, because on Delphi, especially in the Delphi Underground and all correlating (directly and indirectly) forums, I have been a straight shooter in a culture of toxic passive-aggression and aggression-aggresaion long enough that people don't wear their masks when they're talking to/about me, but their real selves.
So yeah. I mean, grass is green, the sun is bright And a triangle has three points and three sides. People who want to allege otherwise can direct that foolery elsewhere.