There was some discussion of this HBO series in comments on this post, in which all agreed that the show is very good and that Kate Winslet's performance is extremely good. When I last commented there I hadn't seen all seven episodes, but I have now, and so can make my concurrence final.
It's a crime drama, and the production as a whole is worthy of comparison to the best contemporary work in that line: Broadchurch, for instance. "Mare" in the title is the name of the principal character. As far as I noticed, the odd name is not explained until well into the series, and then only in passing: it's short for Marianne (Maryanne, Mary Ann...whatever). She's played by Winslet, and is a middle-aged, divorced, working-class woman living in a small Pennsylvania town, where she's a detective on the local police force, like her father before her.
In addition to being a good and well-told story, the series is a realistic portrait of a failing culture: broken families, drugs, aimless young people, and all that. But there are a fair number of film and television productions that do that well. What really sets this one apart for me is Kate Winslet's performance. She is absolutely convincing, and the fact that she's English makes that astonishing. The accent is a very impressive part of that effect, but not the whole thing. If I hadn't known otherwise I would have assumed that the actress playing Mare is a native of the area, because she seems so entirely a part of it.
I don't see all that many movies, and as far as I can remember have not seen Winslet in anything else. I was aware of her as a famous actress, and I knew she was English and had been in Titanic, but that was about all. I figured the person who played the romantic lead in Titanic was probably a glamour girl, possibly not the greatest actress. Well, if she is or was ever a glamour girl, she certainly does not mind stepping into the persona of decidedly un-glamorous women.
There was a time--and although it was a long time ago I was probably an adult--when I thought the craft of acting was over-rated. I think that was partly an impression from the big movie stars of my childhood and youth, who played pretty much the same character in every film, or at least were always instantly identifiable: as John Wayne, Humphrey Bogart, Jimmy Stewart, Katharine Hepburn, Lauren Bacall, and even those of a later generation, like Jack Nicholson. I tended to assume that their one basic character was essentially the person him/herself, and so it seemed that acting was mainly a matter of memorizing one's lines and simulating the emotions of the role, and I thought of the latter as a fairly direct and broad thing.
Of course "simulating the emotions" of the role is not an easy thing to do, even if you're more or less being yourself. But to become, in some not entirely figurative sense, another person altogether, and to speak and behave, down to the most subtle movements of the face, as that person...well, I can't imagine being able to do it. And as I've increasingly understood that, I've increasingly understood that acting is a very difficult art, and most impressive when, as with any performing art, the difficulty is perfectly masked by skill, so that you aren't conscious that you're watching something difficult.
Here's the trailer for Mare of Easttown: