This seems obvious but I guess needs 'official research' to register.

A quote I remember from a coleage - 'They wouldn't give me a pay rate rise, so I gave myself one, by working less hours in a day'

Yeah, I think nobody is gonna tell their boss "I did not like the way you treated me, so I will take a day off for feeling slightly sick". So, while it all sounds obvious, the extent of "idgaf then" is not easy to quantify.

It'll never register, lol.

It'll end up being a tick box moment in some Friday after 5 minute management training document that got completed while thinking about what to do over the weekend.