There’s one person who I’ve had as a manager before that I have told people that if this person ever comes into my management chain again, I will be leaving tha

There’s one person who I’ve had as a manager before that I have told people that if this person ever comes into my management chain again, I will be leaving that company very soon (I’ve said this at more than one company). This isn’t to hold them hostage to me—I just won’t work with that person ever again. It’s also true that the wrong person can disrupt a team that was previously running smoothly. So, yes, “we didn’t like hanging out with her/him” is a perfectly legitimate reason to separate someone from a team.