the.com/preoccupation
A thought that moved into your head and never paid rent.
means A mental fixation or concern that quietly hijacks your attention before anything else gets a turn.
from From Latin praeoccupare, to seize beforehand — literally grabbing the spot before anyone else, including your better judgment.
Military rootOriginally meant occupying territory before the enemy arrived.
Prefix logicPre means before; occupatio means a seizing or taking.
Modern driftShifted from physical conquest to mental squatting.