Staying with the theme of reliably excellent movies I thought of Who's Afraid of Virginia Woolfe. Taylor and Burton, together near the very end, when their real life mirrored the dark theme of the movie (booze and a crumbling marriage plus a bit of lunacy), both deliver fabulous performances. Of course Sandy Dennis is also indispensable as is George Segal (who keeps looking around wondering WHAT the hell is going on here! Not that that stops him from boning the professor's wife.)
The entire movie (except the last few minutes in the bar, where there's one tired barkeep) focuses on these 4 people, almost entirely in the slovenly house of the older couple, but most particularly on George and Martha - the tenured professor and daughter of the dean as they welcome a new young couple to the university. She's a pretty nasty bitch who plays head games with her husband (and viciously insults him at every turn), who in turn flips it around on her guests and plays head games with them and with Martha as well. When they finally throw down and admit that it's total war, to the death, you get frightened...it gets worse than what they've already been doing to each other?? What the hell are they going to do now?? Well, it all starts coming out in dribs and drabs as they work through the tissue of lies they've lived on for so many years and rip them apart. Burton is honestly hilarious despite the dark themes and tone of the entire production. Taylor is wonderful as the nasty bitch who spews hatred at her husband in front of everyone they know, and the bizarre part is that they really do love each other. That's the hell of it, even though it is funny. Through it all the booze flows freely and Dennis/Segal (Dennis in particular) are caught in the crossfire. Like I say that still doesn't stop him doing the other wife while his own wife is outside.
When you finally find out their most elaborate fiction, and watch as he ruthlessly rips it away from her (hey, they said total war and she's been delivering same all along), you will have laughed, been disturbed, pondered, and been damn glad you weren't George or Martha. Again, this is a dark story and if you haven't seen it, remember that going in - black humor is sometimes quite satisfying. C.S. Lewis might not agree with me.