"JOY is the wild story of a family across four generations [Joy’s grandmother, her mother, Joy herself, and her daughter] centered on the girl who becomes the woman who founds a business dynasty and becomes a matriarch in her own right. Betrayal, treachery, the loss of innocence and the scars of love, pave the road in this intense emotional and human comedy about becoming a true boss of family and enterprise facing a world of unforgiving commerce."
This biopic is about "Joy Mangano [,who] is most famously known for her first product: the Miracle Mop, but she holds more than 100 patents for her inventions, including Huggable Hangers, the best-selling product in HSN history. After starting her career at QVC, she led her company, Ingenious Designs LLC, to major financial success before it was purchased by HSN in 1999. Mangano has been the face of the network ever since, and in her 15th year, she remains one of HSN’s most successful sellers, with annual sales topping $150 million. She’s been named Long Island Entrepreneur of the Year by Ernst & Young, and has twice been honored for her accomplishments in Fast Company rankings of creatives and women in business. As of 2015, Mangano’s net worth is reportedly around $50 million—yet, for all her incredible success, there’s precious little additional information to be found about her. And those articles that do detail her rise to fame are virtually identical, name-dropping all the same inventions, sales numbers, awards, and career milestones you see above.
Until the release of Joy, in which Jennifer Lawrence plays a very Mangano-esque entrepreneur, Mangano has fostered what appears to be a painstakingly curated and protected image while remaining firmly in the public eye. (An example: we attended a cocktail party celebrating her 15th year with HSN, but everything about the seemingly benign event, in which we spoke with Mangano for a few moments, was deemed confidential.) Information about her life prior to creating the first prototype of the Miracle Mop in 1990, though the bulk of the story in Joy, is particularly hard to come by." 

You'll find lots of articles about this movie, directed by David O'Russell (Silver Linings, American Hustle ...), and most of them seem to be focused on what's fiction and what's not. 

Fergus Mason, who authored Joy: The Unofficial Biography of Miracle Mop Inventor Joy Mangano, knows this fact all too well. Of the 36 books he’s written for the biography’s publisher, BookCaps—which specializes in pieces that highlight a lesser-known or sometimes forgotten life—he says Mangano’s story is one of the most challenging jobs he’s taken on. “It was extremely hard to find information, particularly about Joy’s early life,” says Mason. “I had a lot of difficulty filling in gaps, because most of what’s available is about her shopping-channel career and what she chooses to release in interviews. The period between her divorce and starting work on the Miracle Mop was an absolute nightmare to find any information about.”
Which is what makes Joy especially fascinating—it primarily follows the main character through that little-known time from age 10 to 40, which means there are never-before-known nuggets of information about Mangano buried within the narrative. But what’s truth and what’s fiction?

It seems though that David O'Russell mostly cared about telling the story of a strong woman in the light of strong women and the life around them - with all its ironic, hurtful, joyful, inspirational and rough elements. You'll see a tapestry of emotional scenes that have a big impact on that Joy's life and how all that shapes her. 

What I liked about the movie was the way it was told. 

I liked the comical elements in sad moments in the movie, and the scenes when you expect a "BANG!" that turn into rather quiet, attention-soaking seconds, which eventually create a bigger impact (e.g. when you expect Joy to scream at the QVC producer on the phone for not fulfilling his part of the deal she chooses to whisper her anger). Picking up on that example, I found it fascinating that overall the character Joy is a forgiving soul, which makes her strong in a very feminine way. 

I don't know how much of this is true (feel free to research that) but I found it ironic how the director David O'Russell publicly pointed out that he made Joy to tell story of strong and successful women, while he is also known to make the life of actors (especially actresses) hell.

I guess, somehow or another we are all complex, contradictory and maybe even sick people: On the one hand we celebrate individuals for their qualities and on the other hand we treat other individuals incredibly disrespectful. (Here is the article I'm referring to.) 

I always take the contents of news and articles with a grain of salt but there is often a little truth to everything and I try to look at a story from different angles. The emphasis is on "I try".

Sources: Rotten Tomatoes and Vanity Fair