What are signs to you that someone is dangerous? Not in a physical sense but in other ways?

When someone talks about how honest they are, again and again, I start to question their honesty. And when someone avoids my questions, I tend to suspect that they know that I wouldn't like the answers. So I guess for me, evasiveness and bragging about how honest they are. Also, if they NEVER tell me anything that I don't want to hear, that can sometimes be a red flag too.

And one other thing. If they gossip about others, that makes me wonder what they might be saying about me behind my back. And when someone talks about how terrible everyone is that they've ever been involved with, sometimes I start to wonder about them, unless I can see that they're attracted to toxic people. One should keep in mind what the one constant is in all of their stories