ob·ses·sion
əbˈseSHən/
noun
noun: obsession
- 1.the state of being obsessed with someone or something."she cared for him with a devotion bordering on obsession"
- an idea or thought that continually preoccupies or intrudes on a person's mind.plural noun: obsessions"he was in the grip of an obsession he was powerless to resist"
synonyms: fixation, ruling/consuming passion, passion, mania, idée fixe, compulsion, preoccupation, infatuation, addiction, fetish, craze, hobbyhorse; More phobia, complex, neurosis;informala bee in one's bonnet, hang-up, thing"that new car has become his obsession"
Origin
That pretty much describes it -

