I love live theatre. My preference is for scenery chewing plays that depend on good writing. I would, for example, see "Who's Afraid of Virginia Woolf' every couple of years.
I used to go frequently and enjoy plays but after a few years a specific experience showed me how truly magical it could be. It was "Moby Dick", adapted by the great Orson Wells from the book. There was minimal scenery - largely a network of ropes to indicate ship's rigging. The actors were on it, rocking back and forth to simulate ship's movement, as they pursued the great white whale. Suddenly, one actor pointed to the back of the theatre yelling "Thar she blows" and half the audience turned around to see the whale's spout, and then look rather sheepishly at each other.
Another time a version of a Christmas Carol had me in in tears of joy at the end. I had been dreading Christmas as I had had a truly dreadful year, but this really helped me mentally.
I remember reading an interview with Anthony laPaglia about his experience acting on Broadway in Arthur Miller's "A View from the Bridge" with Alison Janney. I had recently seen a local performance of it, and it is like a Greek tragedy that all the way through it you are thinking that this is going to end very badly. Anyway, laPaglia and Janney had a very emotive scene with a full on argument, and unnoticed by either actor, she whacked him on the nose with her teeth, and drew blood. When they were in the wings he then noticed blood running down his face. I so envied the passion and mental involvement that such total immersion in your activity could bring.
For various reasons I no longer go to live theatre and my goodness, do I miss it.