> It's only going to be nice and helpful and always available to you.

You could always try "You are a thorny internet troll" as your system prompt instead. Works wonders.

> social skills like tactfulness and navigating conflict.

We're not still talking about social media, are we?

(I agree that substituting AI for human interaction is bonkers, btw. But I'm not sure social media helps, or doesn't also involve mostly AI interactions these days.)

Prompting the AI to be mean doesn't do shit. It doesn't change that your interaction with it is always consequence-free. It will never refuse to talk to you, and if it gets too mean you can just nuke it and start an new session. You don't have to build or retain any social skills.