Eilis's mother could be a grieving woman who doesn't know what to do with her life. Or she could be a textbook emotional abuser. After Rose dies her first goal is to make Eilis feel guilty for not being around, and as soon as she visits home - she instantly tries to invent reasons for her to stay. Likewise is her reaction to Eilis's marriage to TonyI Have No Daughter or just trying to get Eilis away in case she says something she regrets, and plans to process everything later?
Following the above interpretation, is Rose fully aware of this? And with the knowledge that she's ill, her arranging for Eilis to move to America could be her way of trying to save Eilis from getting saddled with having to take care of their mother.
Given we see Rose emotionally miserable reading Eilis's letters shortly before her death, and no specifics about it are given, did Rose actually die from a secret illness, or did she commit suicide over being trapped in a dead-end life?
Is Eilis a nice girl who made a mistake, or a manipulative, selfish girl, who treated Dolores badly, and certainly treated her two men badly.
Is Dolores a miserable cow, or just someone who reacts the way anyone would through being isolated?
Eilis' bunkmate getting revenge on her behalf by locking the other people out of the bathroom.
Ensemble Dark Horse: Dolores has achieved some sympathy from viewers, as, although she does come across as a bit pompous and standoffish, there doesn't seem to be anything bad about her, and certainly not to warrant the viciousness she gets from Patty, Diana, and indeed Eilis.
Some Anvils Need to Be Dropped: The countryside or your home town is not always Arcadia and sometimes leaving for the unknown is actually a good thing. Leaving home is bound to be full of heart aches and struggles, but homesickness does pass and it can lead to something great. Additionally sometimes small towns can be full of people who are just as nasty as some found in the big cities.
Conversely, though less obviously, the glamour and opportunities of the big city will not automatically lead to a better life as Eilis discovers when she volunteers to work at a soup kitchen.
Squick: Eilis' seasickness on the boat. After frantically searching for a bucket to vomit in (the shared bathroom is locked, either out of spite or by the equally ill occupant), Eilis ends up having an episode of diarrhea instead (complete with sound effects), then later vomits into the bucket anyway.