Lyric discussion by QueenThinksALot 

Cover art for Obsessions lyrics by Marina and the Diamonds

I think the first part is about a woman trapped in an abusive relationship, where the two partners are obsessed with each other, but it is completely unhealthy.

Then the second part, might be about an anorexic or bulimic person who worries constantly about food and being caught eating. The dieting is an obsession.

Actually, I think the obsession is obsessive compulsive disorder. As a sufferer myself, when she says "the crackers were probably bad luck anyway" it's the archetypal thought process an OCD sufferer would go through - something as benign as a brand of crackers is believed to have an enormous impact on the day. It's kind of like superstition but in extreme form; everyday objects are believed to be "lucky" or "unlucky". And wanting to erase nasty thoughts is another particularly pertinent line suggesting this song is written about OCD - repetitive rituals are often carried out in order to erase...