Context
Colleagues arguing about something that doesn't involve you.
Eso no es asunto mío.
That's not my business — clean, simple, the standard way to disengage.
Cheerful detachment — not my problem, not my responsibility, I'm staying well out of it.
Interestingly, this phrase actually comes from Polish ('Nie mój cyrk, nie moje małpy'). Spaniards have their own equivalents.
Context
Colleagues arguing about something that doesn't involve you.
Eso no es asunto mío.
That's not my business — clean, simple, the standard way to disengage.
Context
Drama in a friend group you're not part of.
Yo no me meto en eso.
I'm not getting involved in that — active choice to stay out, not just observation.
Context
Work chaos that belongs to another department.
Eso lo tienen que resolver ellos.
They need to sort that out themselves — assigns responsibility while removing yourself.
Context
Family drama you've wisely decided to avoid.
Allá ellos.
'Up to them' — short, final, beautifully detached. One of the most useful phrases in Spanish.
Context
Watching two friends argue while you sip your drink.
Que se las apañen ellos.
Let them manage it themselves — apañarse is that Spanish verb for muddling through on your own.