detachment. It’s very useful indeed, especially against emotional manipulation (not just by others, but even moreso the emotional manipulation you do to yourself).
Hardest part for me hasn’t been detachment though. It’s been detaching from detachment on occasion in order to move towards activism.
I think the progression is important, at least for me it has been:
Detachment from emotional manipulation
Detach from detachment and actively engage.
I tend to spend more time in assessment than activism, but I’m learning when to step out.