What if someone's always talking to you like you're the bad guy...how do you put a stop to it?

I'd say.. you know? Although I respect your opinion, and value your input, you're really starting to piss me off with the me always being the bad guy.

But then all we have is your side of the story. Are you the bad guy?

Maybe you’re not the bad guy. Perhaps they’re just inherently negative. Throw that back at them and walk away after a “Ponder that.” statement.

Talk to them the same way

I've just been through this. I start BEING the "bad guy". Give them what they seek and let them see what a "bad guy" is really like.
Yeah, I know. "How childish, how petty, how immature, I must hate myself, narcissistic, It makes me feel good, blah blah blah yak yak yak" 🙄😂

Get Straight to the point....

Remove their access to you

Slow them what bad is

very strongly tell them KNOCK IT OFF!! ENOUGH ALREADY!!