Everything Geoffrey does for Charles Kingman after he finds out about his cancer. He takes him in, takes care of him, even helps him take heroin for the pain, all while hiding the illness from the rest of the cast and bearing the brunt of their displeasure with the way that Charles treats them. He takes all of the bad things about Charles in stride.
Charles: Geoffrey, the illness is not a pleasant thing to witness. I don't sleep well, I've problems keeping down my food and my body makes vulgar sounds that I can't control.
Geoffrey: Well, I have lengthy conversations with an invisible companion.
Charles: Shall I set three places for dinner?
Becomes a heartwarming Tear Jerker when you find out that Charles' actor William Hutt was dying of leukemia when the season was filmed.
Darren Nichols' wholehearted acceptance of the fact that his entire approach to Romeo and Juliet was completely wrong, and his resorting to the infamous "Belkovski Exercise".note in which, after weeks of dull, boring rehearsal, he gets his entire cast and himself to loosen up by shutting themselves naked in a blacked-out rehearsal room with a load of flourescent paint. It works.
Darren: Have. A Good. Grope!
Richard finally getting to courage to pursue his life's dream of being in a musical, and doing pretty well at the audition. At least until the dancing part.
Anna bonding with the Bolivian folk band and doing everything in her power to keep them from being deported. They appreciate her and pay attention to her like no one else at the theater does.
Sophie confessing her love for Paul.
The final performance in every season, particularly the series finale King Lear.
When Geoffery announces his resignation in front of his actors, and Frank and Cyril both stand up and tell him that he can't leave. In spite of the grief Charles caused for them, they were still loyal to Geoffery.
For some reason, this scene always chokes this troper up. Watching sweet Kate leave with Jack in the limo, Geoffery and Ellen getting back together for the first time in years (made even better by the fact that Paul Gross and Martha Burns are actually married to each other in real life), and Michael Polley's beautiful voice singing "Memories of You" in the background.