12 Angry Men is one of the great American dramatic films and an absolute master-class in writing: an enthralling story set almost entirely in one room and consisting of nothing but, well, twelve very different men debating back and forth. It’s what happens when you have a first-class director (Sydney Lumet) leading a first-class cast (Henry Fonda, Lee J. Cobb, E.G. Marshall, Jack Klugman, Martin Balsam, John Fiedler, etc.) through a first-class script. If you haven’t seen it, you should do so at the first opportunity.
Now, I don’t know much about YouTuber Fringy, except that he’s one of the ‘Efap’ crew, of whom (apart from Mauler) I’m mostly rather leery about. But this video of his, examining the character writing in the film, is excellent.