All the facts point to this being about bullying. Take the grade school incident of Oscar stomping on Gloria's school project and crushing it. Even though Oscar tried to present himself as a different person the second time around when rejected for Joel he became abusive, psychologically then physically. The climax is when Gloria, who has gone to Seoul, shows up in the park as the monster, picks up and tosses Oscar, finally overcoming her fear of Oscar, which presumably she has carried for years and is at the root of her alcoholism. Hathaway does a commendable job of making you dislike her character, as Oscar does in getting you to like his character until Gloria spurns him and the tables turn. You end up cheering for her in the end as she overcomes her demons...
